# Talk:Electric motor/Archive 1

## Electric vehicle mass production

You may have seen the Tesla electric sportscar http://www.teslamotors.com

You may have even seen the T-Zero electric sports car http://www.acpropulsion.com/acp_faqs/faq...

These two cars show that it is now possible to build electric cars that can out-accelerate a Ferrari, and go 250 - 350 miles on a single charge. But both these cars are very expensive.

So who else is working on electric cars?

Would you believe China? They have to work on EVs. There won't be enough oil to support China's future economic growth.

I drive an old electric vehicle. I also have friends with electric vehicles. Some of them have recently been able to buy some amazing, cutting-edge EV batteries from China - example:

These batteries are better, and cheaper than the ones in those \$100,000+ sportscars above. If you look at the chart, you'll see they are as cheap as lead-acid batteries, and they hold up for 1100 charges, twice as many charges as the other LI-Ion batteries on the chart.

Now, look at this car:

It's a Chinese electric car, which will be imported into the USA next year. The driving range is almost as good as those sports cars above. But it only costs \$28500. And that price could get a lot cheaper. —Preceding unsigned comment added by Nadyes (talkcontribs) 09:41, August 14, 2006

## This moves contents box to top

I think this article should be made more systematic. IMHO the difference between the various motor types is not made clear enough in this article. I think I may even have the skills to do it.

I would prefer a subdivision in the following types.

• Motors with an armature with coils and a commutator. This is the classic DC motor. The stator can have permanent magnets or electromagnets as well. In the latter case there is the distinction between series and shunt motors, both can run on AC as well as DC.
• AC motors either with a permanent magnet rotor (synchronous) or a so-called squirrel cage rotor (asynchronous or induction motors).

## Do universal motors self-destruct from overspeed when operated on AC?

A recently added comment suggests that universal motors can self-destruct from overspeed if operated unloaded. While it's true that powerful DC series motors can definitely self-destruct if operated unloaded, I've never heard of an example of a universal motor self-destructing from overspeed when operated on AC. I've always assumed that it was the inductance of the motor acting to limit the current that prevents the destruction, but I've never actually seen any supporting data one way or the other. Certainly household universal motors (such as blenders, Dremels, power drills, and the like) seem to live just fine loaded only by the friction of their bearings and brushes.

Atlant 12:34, 26 January 2006 (UTC)

The problem with DC motors is primarily with complete loss of field current in unloaded shunt and separately excited motors. With series motors, there could be a problem if the load characteristics and the motor's speed-torque curve are such that loss of load could allow a destructive speed. With a series motor, there will always be field current as long as there is armature current. Products like blenders, Dremels and drills are designed to run without an external load. An important part of the internal load is windage. Some of these products have a little fan on the motor shaft to cool the motor. Even without a fan, the windage torque likely exceeds the brush and bearing friction. Altering the design of the product by removing the fan or gearing could conceivably cause a destructive overspeed. Blocking the airflow in a vacuum cleaner certainly unloads the motor considerably and allows a speed increase. I suppose that could lead to failure especially if the fan is already damaged or unbalanced due to vacuuming up rocks or some such thing. --C J Cowie 16:19, 26 January 2006 (UTC)

Afaik, most if not all vacuum cleaners use the air flow through them to cool the motor; prolonged blocking of the flow is likely to make the motor overheat. Regards, Nikevich (talk) 21:48, 21 April 2009 (UTC)

## hack....why not?

If I have

| NS<rotor>SN|

basically 2 current carying coils fixed in space and magnets mounted on the rotor (such that the polarity facing the coils is the same), is it not a brushless DC motor which doesnt need induction or stepper drive?...and if no, why not? The idea simply is to remove the magnet from the outside onto the inside and rely on the fact that the fixed in space current carrying coil induces a force on the magnet which is mounted on the rotor.--alokdube@hotpop.com

Your rotor will probably rotate 90 degrees and then stop. All electromagnetic motors depend on some arrangement that either:
1. Creates a moving magnetic field (as in induction motors, synchronous motors, and brushless DC motors), or
2. Has some switching arrangement to keep the magnetic fields fixed in space but at a position where they can impose a continuous torque on the rotor (as in commutator DC motors).
Atlant 13:58, 17 February 2006 (UTC)

Please note the following in the above a. the current is in the same direction in both the coils on either side of the magnets b. the magnetic polarity is always the same when facing the current coils c. the current carrying coils are fixed so as seen from above if the current flows upwards in the "fixed" coils, we get the flux into the page, on the Left side and outside the page on the right side. Hence the torque does not balance out. if u want u can always insert 2 more coils on the front and back side. This is being tested right now. A simple way to imagine this is, think of Oesterd's experiment, place a back to back magnetic needle/annular ring magnet in a mesh of wires where the current always flows in the same direction/up to down etc. more like: | | | N--S-rotor-S--N | | |

--alokdube@hotpop.com

It's a little hard to follow your description, but I think what you might be describing is like a squirrel cage motor, but with the difference that the rotor field is generated by passing a current through the squirrel cage between permanent magnets. I can't see how this would rotate, since the field isn't rotating. What is going to set up a torque? Maybe I've misunderstood your description.Graham 06:39, 21 February 2006 (UTC)

Thansk for your comments, I do know what a squirrel cage motor is. This is not the same thing. the torque could be setup as the pole, say north is closer to the current carrying wire as compared to the south consider this

<wire current flowing into page> N-----|-S <wire current flowing into page>

in other words the magnetic needle is hinged at a point closer to one of the poles.

The other arrangement could be is to make the magnets outside (like the outer rotor fan) and ensure that the coil inside carries current in the same direction.

is an example of the field plot

the Blue circles are the coils carrying current into/out of the page and perpendicular to the plane of the page The rest of the circles and dots indicate points with equal magnitude of B.

Ok found a pancake motor, very similar thing except that because the field sees alternate N---S---N---S it has to be commutated. If the motor always say N or always S there would be no need for the same,

--Alok

## Tesla's Three-Phase electric motor

A model of a synchronous 3 phase electric motor in my project is here, so it is OK it could be released under GFDL, as far as I am concerned.

The problem was I was not sure which background to choose, and which version of rendering, and whether the image quality satisfies article at all, compared to DC motor rendered in Blender.

3-phase engine is rendered in POV-Ray, and it is easily customizable in regard to number of R rotor poles, S stator poles, other parms, and N the number of wires in each coil. I can easily modify POV-Ray 3D model according to your suggestions.

Here are the images:

Simple three-phase engine model. Arrows of magnetic field could be added to clarify how engine works ...
The same with white background, to fit with the rest of the page ...
Some more vivid colors, according to advices of a reproduction photography expert. But I was not too obedient, since I want to preserve photorealistic look contrary to artificial colouring to add clarity. Is that the right approach?

Please choose the variant, or propose suggestions. I think three-phase engine is not clearly explained with just a photo of a motor that is not even opened (which is also an option with POV-Ray!!!)

I hope to get some feedback.

There were ideas to clarify rotating magnetic field with a series of pictures showing how vectors of phases add into a single rotating vector - or a movie could do. I just need to convert what was done from Quicktime to MPEG or Ogg. (Recommend a tool?)

Greetz all. -- Mtodorov 69 07:54, 10 March 2006 (UTC)

i'd go with the third one, it's more defined.

Those illustrations are extremely helpful in explaining synchro fundamentals! The only major difference between yours and a "real-world" synchro is that the stator windings are distributed, so the poles are likewise almost continuous. Most unfortunately, the illustrations I've seen (other than in Navy training manuals) that try to explain synchros are pretty wretched! Best regards, Nikevich (talk) 21:57, 21 April 2009 (UTC)

## Textbooks

The Bedford & Hoft text was originally cited as "Bedford and Hoft, unnamed book on power electronics, outdated." I assumed it is the same book that I have and put in a complete citation for it. It is only indirectly related to this article. It should be a reference for Variable Frequency Drive. --C J Cowie 17:33, 12 March 2006 (UTC)

## limits to efficiency

Heat engines have both the Carnot efficiency and a practical upper limit due to heat transfer. Some people claim that Carnot's cycle does not apply to electric motors. I'm wondering if there is any theroetical limit to efficiency and whether this corresponds to a temperature (${\displaystyle T_{hot}}$) with some physical interpretation (say ionization temperature of the windings). What stops us making a 100% efficient electrical motor? --njh 18:43, 12 March 2006 (UTC)

The Carnot cycle describes a process by which a heat engine converts energy in the form of heat stored in a working fluid to mechanical energy. An electric motor converts electrical energy to mechanical energy in a manner that is quite different from a heat engine.
What prevents us from making a 100% efficient electrical motor is mostly friction. There is mechanical friction due to moving parts sliding against each other the just as happens in a heat engine. There is something similar that happens when electrons flow through an electric wire. The electrical resistance of the wire works against the flow of electrical current and causes electrical energy to be converted to heat. Changing magnetic fields also cause heat in the iron parts of the motor. Any electrical energy that is converted to heat reduces the efficiency of a motor below 100%. With today's technology, large 3-phase AC motors are often 96% efficient. Using superconductors it may be possible to make motors that are quite close to 100% efficient.
Although electric motors are quite efficient, most electrical power is generated using heat engines or by other means that are less efficient than electric motors. There is also energy that is lost as heat is transmitting electricity from the power station to the electric motor.
C J Cowie 21:51, 12 March 2006 (UTC)
I think the true answer is deeper than that. There are many examples of energy conversion that at first glance seem to avoid carnot's cycle, yet when deeper analysed reveal that thermodynamics is hard to escape. (I suspect, though nobody has given me reasons either way, that carnot applies to every energy transformation)
Some examples are fuel cells, solar panels and direct nuclear radiation power conversion. All of these at first glance appear to avoid carnot efficiency (for example, a fuel cell might get 85% efficiency operating at 600K, when the carnot cycle might seem to imply 50% as an upper limit. In fact the cycle is operating from the flame temperature or something.)
All electric motors become less efficient as they get hotter, which might be a symptom of a hidden cycle (or just coincidence).-- njh 00:00, 13 March 2006 (UTC)
(I suspect, though nobody has given me reasons either way, that carnot applies to every energy transformation)
Your suspicion would be wrong, sorry.
Atlant 00:46, 13 March 2006 (UTC)
Could you give a reference that covers this? --njh 01:04, 13 March 2006 (UTC)
Pretty much any good electrical engineering reference on rotating electrical machinery should make this clear to you, but you might want to consider the efficiency of motor-generator units. They can move a surprising amount of electrical power through them (with a full conversion from electrical power to mechanical power and back to electrical power) with a relatively small development of waste heat.
Atlant 01:32, 13 March 2006 (UTC)
That doesn't prove anything, it just shows that the likely Thot is very hot. --njh 09:40, 13 March 2006 (UTC)
As I wrote above, the Carnot cycle describes a heat engine process. An electric motor clearly does not involve a heat engine process. An important Carnot principle can probably, in some sense, be applied to many if not all energy conversion processes.
In Cengle & Boles Thermodynamics an engineering approach, it is stated: "Factors that cause a process to be irreversible are called irreversibilities. They include friction … electric resistance …. The presence of any of these effects renders a process irreversible. A reversible process involves none of these." and the Carnot principle: "The efficiency of an irreversible heat engine is always less than the efficiency of a reversible one operating between the same two reservoirs."
The process of an electric motor is reversible except for mechanical friction, the friction between moving parts and air, electrical resistance, magnetic losses and perhaps some other small items. It is only these items that prevent an electric motor from achieving 100% efficiency.
Increasing the operating temperature of a motor increases the electrical resistance of the copper and aluminum conductors. That would tend to reduce the efficiency. Temperature changes also change mechanical clearances and the dimensions of air gaps in the magnetic circuit. Hard telling what effect that has.
C J Cowie 01:58, 13 March 2006 (UTC)
Thats all very nice, and I am quite aware of that, but it doesn't answer my question. I spoke with a physicist today and he was of the opinion that there was more to it than these surface issues. One interesting thought experiment occured to me: imagine a heat engine driving an electrical generator which heats the hot side of the engine. So the question then becomes one of what the highest temperature achievable with an electric source is (which is certainly very high!). MHD has been shown to do work to at least 15 million K. I shall go digging. --njh 09:40, 13 March 2006 (UTC)

## Switched or variable Reluctance motor?

Sure Ive heard of such a beast- but its not mentioned in the article. Is this just an omission?--Light current 05:26, 31 March 2006 (UTC)

Are these the same as stepper motors?--Light current 08:36, 31 March 2006 (UTC)

I think switched reluctance motors are a variety of stepper motor (with an unmagnetized rotor).
Atlant 14:03, 31 March 2006 (UTC)

OK. Shouldn't these types be put in the article?--Light current 17:32, 31 March 2006 (UTC)

I haven't yet read the whole article, but I suspect that these are now not exactly rare in industry. Try a periodical called (or formerly known as !) Power Control/Intelligent Motion (PC/IM). Regards, Nikevich (talk) 22:03, 21 April 2009 (UTC)

## Repulsion motors and other types

Thank you very much for all the hard work you put in on the repulsion motor section of electric motors. Great addition to the article. Pcb21 Pete 07:24, 12 April 2006 (UTC)

And on that note another "missing topic" that I am trying to find a home for is reluctance motor. As Electric motor is our main article in this area I would like to redirect there, but I don't want to do such a ham-fisted integration job as I did with repulsion motor. Are you able to help out? Pcb21 Pete 08:27, 12 April 2006 (UTC)
If I have time, I will look into that. See also discussion above. There are probably other types of motors, design variations and motor related terms that should be considered for inclusion in this article. --C J Cowie 15:52, 12 April 2006 (UTC)

## Nano motor

I think that consideration should be given to moving this section to one of the nanotechnology articles. It isn't totally out of place in this article, but it is quite different from the types of motors described here. There is already a nanomotor article, but what is described there may not be the same as the nano motor described here. There is also something like this described in the micromachinery article. See also: list of nanotechnology topics and Category:Nanotechnology. --C J Cowie 00:47, 17 April 2006 (UTC)

Well it IS a motor, and what a beautiful animation! It would be a pity to lose it to another page.--Light current 00:55, 17 April 2006 (UTC)

## does horsepower really equal 750 watts?

I have a 3.5 "horsepower" chainsaw which only draws 12 amps at 110 volts. I don't see any discussion of horsepower in this article but elsewhere I have seen that at 100% efficiency 1 HP would be 750 watts. I doubt that 100% efficient motors exist, but perhaps this definition is arbitrary and there are others, perhaps in terms of torque or something. I doubt even marketers could get away with a bold face claim of 3.5 horsepower that violated the laws of physics.--Poodleboy 19:55, 23 April 2006 (UTC)

Used to be about 746 W per horse when I went to school (mind you, horses were big in those days). You have measured it on no load havent you? Try cutting a tough trunk and then measure the current!--Light current 19:59, 23 April 2006 (UTC)
No, I haven't measured it at all. 12 amps is just the UL rating on the device. It is a Remington 3.5 horsepower electric.--Poodleboy 09:13, 24 April 2006 (UTC)
For UL listing, the design engineers (not those devious marketing people) provide ratings on the motor for real world sustained operation. You can calculate sustained horsepower from Hp = (Volts X Amps X Efficiency X Power factor)/746. Estimating efficiency and power factor at 0.8 each, a 12 amp motor will produce about 1-1/4 Hp. (Power factor tells us how much current is used to pproduce power as opposed to magnetizing the motor).
Marketers are clever and devious. They don't usually actually lie, but they often resort to rather obscure versions of the truth. Horsepower advertised for consumer products is usually the "peak horsepower." That is the absolute maximum power that the motor can deliver for a very brief time. Peak horsepower is often measured by increasing the load torque applied to the motor while plotting a graph of the torque vs. speed. The motor's speed decreases as the torque increases and the motor quickly comes to a stop or "stalls" when the peak torque is reached. The peak power is calculated by HP=torque*RPM/5252. Don't try this at home. The manufacturer likely performs this test on the motor alone not the assembled chain saw. Their power supply is capable of safely supplying more current than the typical household outlet can supply. --C J Cowie 21:24, 23 April 2006 (UTC)

A horsepower is an amount of Mechanical work equivalent to 33,000 foot pounds per minute. It dates back to actual horses and I guess your standard nag could be counted on to, for example, raise a 330 pound weight 100 feet in one minute. And yes, it's roughly equivalent to an energy input of 746 watts.

Chain saws, vaccums, and other home appliances that make exagerated claims of horsepower while running off of (say) 15 Amp 120 volt circuits (where the circuit breaker trips somewhere just north of 1800 watts) are, basically, lying, although they'd probably claim they're merely describing the hypothetical peak power of the mechanism.

Atlant 12:32, 24 April 2006 (UTC)

Maybe these ratings are peak horsepower? I've searched the internet, and there are concepts such as service factor and uprated motors, etc. While I found some authoritative discussions of the concepts on commercial site, I haven't found any standards, although the service factor concept seemed to come from some standard. Wikipedia probably could help by filling this void. Here is a link to a pool spa site for gosh sakes, that was about as authoritative as any [1]. Is "peak horsepower" really as useless as some internet articles say? My concept so far, is a little analogous to momentum, a free wheeling motor suddenly brought to a stop, might be applying larger amounts of force that it could continuously, that that peak of power might be useful. For instance, in a chain saw working with a dull chain having trouble cutting a log, it helps to let it rev-up and then the high initial speed has a little more cutting power for an instant, until the chain slows. There are probably analogous examples in other applications, but I don't know if this concept can be made rigorous. Another example, a motor used for pulling something, might be able to use peak horsepower for an instant to get the object moving, overcoming the co-efficient of static friction, and then complete the pulling operation for however long it takes within its standard or brake horsepower rating. Given two motors with the same brake horsepower rating, one with a higher peak rating might be able to get this task started and complete it, while the one with the lower peak rating wouldn't be able to get it started. However, using peak horsepower this way makes it seem a lot like torque?--Poodleboy 09:27, 4 May 2006 (UTC)
For a better understanding of this sort of marketing tactic that uses bizarre special-case and nonstandard product testing rules, you should read about the much-despised PMPO measurement used by manufacturers of low-quality audio components, to make their audio equipment seem better than it really is. DMahalko 08:00, 1 June 2007 (UTC)

I believe what was stated here right above us: These peak horsepower numbers are derived by operating the motor briefly on an (essentially unlimited) power circuit. In that way, for the few seconds before the motor reaches its thermal limits, the vendor can claim truthfully that the motor was developing the claimed five or six horsepower. Of course, because of excess heating, this power level can only be maintained briefly and in the real world, it might well trip the circuit breaker, and there's no way to load your (e.g.) vacuum cleaner to actually require five or six horsepower, but it sure makes a great advertising claim, no ;-) ? At least in your chain saw example (or in traction motors), there's some basis whereby you could actually use this amount of peak mechanical power. But the vacuum cleaner claims are just silly.

Atlant 12:06, 4 May 2006 (UTC)

What limits their power draw on a 15amp circuit? Is the test performed with some kind of limiter removed?--Poodleboy 09:34, 5 May 2006 (UTC)
The circuit breaker or fuse is the main limiting factor. In addition, the high current will probably cause the voltage to drop a little. Even when the current is available, it is difficult to hold the motor at the peak torque point because the slightest increase in the load above the peak capability will caus the motor to stall. The peak torque point on the torque vs. speed curve is not a stable operating point. --C J Cowie 13:10, 5 May 2006 (UTC)
It must be something short of the circuit breaker, because that is not tripping, and it only limits by tripping.--Poodleboy 14:53, 7 May 2006 (UTC)
The motor will only draw high current and trip the breaker if it has a heavy load. The test to determine peak horsepower requires a load that can be carefully controlled and adjusted and measuring equipment that records torque and speed data as the torque and speed change rapidly. Once the torque and speed data has been recorded, horsepower is calculated. Because of the difficulty of controlling the load and making the measurements, it is generally not possible to perform this type of test on an assembled saw, vacuum cleaner of whatever. Only the motor is tested. --C J Cowie 20:24, 7 May 2006 (UTC)

## Comparisons between US and UK domestic electrical installations

Yeah. I was wondering about that!. How much current can you get out of a US wall socket at 110V? 120V (Ie nom rating, not cable frying, fuse busting current)--Light current 21:35, 23 April 2006 (UTC)

In bathrooms, kitchens and dining rooms, 20 amp circuits are required. I believe that 15 amp circuits are permitted everywhere else. The nominal voltage is 120 volts. Circuit breaker and fuse ratings are the same as the nominal circuit service current ratings. --C J Cowie 21:56, 23 April 2006 (UTC)

Bathrooms??? You dont allow mains outlets in bathrooms do you? V. dangerous when your in the altogeher and wet you are a very good conductor!!--Light current 22:02, 23 April 2006 (UTC)

Bathroom, kitchen and outdoor outlets are required to be protected by ground fault interrupters. Hand-held hair dryers now often have GFI protection built into the product. --C J Cowie 22:06, 23 April 2006 (UTC)

Aha. We have solid cross bonding of all accesible conductive parts in bathrooms to create an equipotential zone and no sockets allowed. Even the light switches have to be outside or cord pull types if inside.--Light current 22:35, 23 April 2006 (UTC)

The GFIs are quite effective, but bathrooms here had outlets before GFIs were invented. Installations are supposed to be brought up to code when repairs or improvements are done, but there are lots of unprotected outlets in older buildings. Switches and lights are not usually on GFI protected circuits, but any metal that is not part of the circuit is grounded with a separate ground wire that does not carry current. --C J Cowie 22:34, 23 April 2006 (UTC)

What current are your GFIs set at, and can you survive this current for the time it takes to trip out?--Light current 23:21, 23 April 2006 (UTC)

I believe that they are very effective at preventing death by electric shock. I don't know the specifics for USA designs, but I suspect they are similare to the EU designs. Look at the Residual-current device article. --C J Cowie 23:41, 23 April 2006 (UTC)
We brits are about the only country in the world that don't accept sockets in bathrooms (at least in our accepted standard BS7671, however i know of at least one person who got a schuko socket wired to german regs past building control). Most countries assume that people have enough common sense not to use hand held appliances while in the bath! Plugwash 23:48, 23 April 2006 (UTC)

Whats a schuko? Most countries must have more intelligent people than we have here!(Drying your hair whilst in the bath uused to be a favorite)--Light current 23:57, 23 April 2006 (UTC)

A classic horror in past years was the lowest-cost five-tube (valve) AM radio in the USA with no power transformer, and series-connected heaters connected across the line. The chassis was plated (?) steel, and one wire of the (non-polarized-plug) power cord was soldered to the chassis. As sold, no exposed metal was connected to the chassis, but the housings were made of early plastic which broke easily. Somebody dropped the radio, the housing shattered, and maybe a tube broke, but it either continued to work (with even less bass output) or could be fixed by replacing a tube. Sooner or later, some poor soul would take it into the bathroom and place it onto the edge of the tub. (I don't mind at all if this comment is moved elsewhere.) Regards, Nikevich (talk) 22:12, 21 April 2009 (UTC)

BTW Plugwash, I think this talk could be moved to a more suitable page. What think? Can you name one?--Light current 23:58, 23 April 2006 (UTC)

Schuko is the manufacturer of a common European plug/socket family.
Atlant 12:26, 24 April 2006 (UTC)

Shucks!--Light current 14:38, 24 April 2006 (UTC)

## material used to manuf. brushes used in a.c & d.c. rotating machine

Hi

Can anyone tell me what is the most common material used to manufacture brushes used in a.c. and d.c. rotating machines —The preceding unsigned comment was added by 84.68.243.36 (talkcontribs) .

Carbon or a Carbon/Copper composite, I think.
Atlant 17:56, 2 May 2006 (UTC)

i think carbon wit copper cos carbon might detoirate fast but in my text it says only carbon brushers by yunusmecci@hotmail.com

Here's what looks like a good reference:
http://www.repcoinc.com/carbon_brushes_fld/reference.asp
And it looks like most brushes are varieties of carbon but yes, some are loaded with metal powder, especially where the lowest resistance is required.
Googling for "brushes carbon commutator material" produced lots of data.
Atlant 15:19, 3 May 2006 (UTC)
When motors and generators first appeared, the brushes really were brushes of copper wire. They were carried on a moveable ring with a handle. The handle moved the brushes around the commutator and the aim was to find the position of minimum sparking (the process was known as 'rocking the brushes'). As the load changed, the brushes needed to be moved to minimise the sparking once again. As motors developed, 2 systems were developed to avoid the need to rock the brushes. One was interpoles between the field poles (the article doesn't mention them). They were wired in seies with the armature and arranged such that they reversed the distortion of the field caused by the armature's own field. The second development was 'high resistance brushes'. These were now made from a formulation of carbon and copper and even though they present a resistance measured in milliohms, they were high resistance compared to the original copper wire brushes. This 'high' resistance limits the spark caused as the brush breaks contact with a commutator segment by effectively raising the resistance of the contact as the segment moves beneath it, rather than suddenly breaking connection. On some particularly high current/low voltage motors, such as automotive starter motors, the brushes contain more copper than carbon, to the extent that they almost look like solid copper.

## Question on Dates

The article refers to Faraday and Maxwell in the 1820s. Maxwell was born in 1831. I didn't want to just take the sentence out... Kephart 05:47, 10 June 2006 (UTC)

Thanks for noticing. I reworded the sentence. --Heron 11:11, 10 June 2006 (UTC)

## Citation needed

This is highly dubious. Removed till a citation is provided.

[rotating magnetic field principle] was employed by scientists such as Michael Faraday in the 1820s and later James Clerk Maxwell

204.56.7.1 15:40, 28 June 2006 (UTC)

Someone with drawing skills could add a diagram to show how either of these motors works.

Discuss briefly the number of poles and the number of phases of an AC motor. Explain why the one-phase AC motor needs a startup winding or a shaded pole.

Discuss that brushless DC motors and stepper motors are constructed similarly to a permanent magnet rotor AC motor, but that they are driven by switched DC currents instead of AC. The existing info on stepper motors is a good starting point.

The electrical generator article needs even more work I think. At least it should be mentioned that most electric motors can be used as a generator and vice versa. Principal construction of both is the same. Mrlennart 10:23 Apr 26, 2003 (UTC)

The sentence that starts "In order for it to operate it must always run slower than the frequency of the power supply feeding it causes the magnetic field in the motor to rotate,..." is not grammatically correct, but I am not sure how to rewrite it properly. Nanobug 12:15, 5 Aug 2003 (UTC)

I have removed the following section as Michael Faraday demonstrated the electric motor in 1821 and discovered the dynamo effect in 1831. Maybe somebody could check the Maxwell quote.

== Some history and interconnection ==

"The construction of an electric motor is very similar to that of a dynamo. In fact, a machine can be built that acts as either a motor or a dynamo. Historically, the electrical generator (dynamo), came before the motor. It was not until a workman mis-wired a generator, that the public came to understand that mechanical motion could be generated from an electrical source. James Clerk Maxwell called the electric motor the single greatest invention of his time." Tiles 07:05, 15 Oct 2003 (UTC)

I am gratified that I reproduced similar information and quote, 2.5 yrs later, on another talk page. My source was IEEE Spectrum, in the 1970s. --Ancheta Wis 09:58, 21 March 2006 (UTC)

I've uploaded a photo of a DC motor in a model railroad that maybe some of you could find interesting, here's it: File:Motor-dc.JPG

I would like to see a better explanation of three-phase motors, hopefully with a diagram. I can't find any information on these systems on the internet. Perhaps a different term is more appropriate?

Technical problem : brushless can't be DC motor !! all the brushless engine have a electronic module to convert the DC to 3phase AC !

From a purely technical point, that may be true, but the universal convention is to refer to these motors as "brushless DC motors", doubtless because the power fed to them is DC. The internal workings of the motor are a black box as far as most folks are concerned.
Atlant 16:54, 6 Jan 2005 (UTC)

## Synchronous Condensors

As far as I know, Synchronous Motors have a theory of their own and the main application is power factor correction which is not mentioned any where. Have a look at Synchronous Motors. --Electron Kid 13:43, 30 October 2005 (UTC)

All motors and generators have a lot of theory in common, but the theory divirges as you get into the details. In engineering texts on rotating machinery, a common approach is to start with synchronous machines and then move on to induction machines and then to DC machines. In each case, the machine can operate as either a motor or generator, but generator controls differ from motor controls, and machines are usually designed for optimum performance as either a motor or generator. Induction machines are not designed for use as generators, but induction motors often serve a dual purpose as either motors or brakes/generators. Induction motors are used for most applications because they are the most simple in their mechanical construction and in the usual start/stop control system. That makes them less expensive. Above 1000Hp or so, synchronous motors are used for more application because they are more efficient and some aspects of construction and control begin to favor them or at least not disfavor them. I don't think that a majority of synchronous machines are used strictly for power factor correction, but that application still deserves to be mentioned. As far as I know, AC machines intended to be only generators are always synchronous. --65.26.227.118 16:26, 30 October 2005 (UTC) I didn't mean to be anonymous. --C J Cowie 16:29, 30 October 2005 (UTC)

## Three Phase Rotating Field Diagram

The excelent animated picture of the rotating field in a three phase machine needs to be located with the relevant paragraph. If nobody objects, I'll shift it (unless someone beats me to it. 86.132.205.37 16:35, 2 June 2006 (UTC)

This animation looks interesting, but what does it actualy illustrate? This is the first time I have ever seen a 3-phase motor with a field illustation like this. Imo it should be deleted as confusing. KjellG visitor from no.wiki —The preceding unsigned comment was added by 85.165.119.57 (talk) 23:31, 9 March 2007 (UTC).
The GIF animation has a number of confusing "shadows" and is very difficult to understand unless you have a good knowledge of vector summation. A more common way of illustrating the field is one single vector rotating in lieu of the rotor illustrating that the three coils generate a constant rotating field in the middle of the motor. Looking forward for someone to make a better illustration. KjellG 23:07, 15 September 2007 (UTC)

An anonymous editor (68.165.190.225) left the following message in the article:

But how do you wire it?

(referring to stepper motors and digitally controlled servomechanisms, I think). --Heron 12:41, 20 Oct 2004 (UTC)

## Reducing the armature current

An anonymous editor (User:163.1.179.126) has inserted the following text:

Quite counter-intuitively, reducing the armature current will usually make the motor turn faster

I think this is wrong. It is the reduction of FIELD current that causes the motor to run faster (owing to a reduction in the generated counter-EMF with the reduced strength of the magnetic field produced by the field coils).

Which is correct?

Atlant 21:39, 6 Mar 2005 (UTC)

(Apparently, someone else agrees with me since they reverted the new statement out.)

Atlant 13:21, 7 Mar 2005 (UTC)

## Common concepts between single-phase and three-phase headers

Someone just edited valuable data into the "Three-phase induction motor" head, but the text is equally applicable to the earlier "Single-phase induction motor" heading. Shall we just move the new text up there (so "Single-Phase..." continues to be a kind of master description? Or shall we do more-radical surgery, perhaps creating the following headers:

• Induction motors (general concepts of the rotating magnetic field and induction into the armature/rotor)
• Three-phase induction motors as the obvious real-world simple implementation of the theoretical induction motor
• Single-phase motors as a special case with the need for starting provisions

And then, of course, a similar new alignment for synchronous motors:

• Synchronous motors as a variation on how to use the rotating magnetic field
• Three-phase synchronous motors (and the need for starting provisions compared to induction motors)
• Single-phase synchronous motors

Thoughts anyone?

Atlant 20:19, 14 May 2005 (UTC)

## Number of poles

I was taught that the number of poles of a motor is *always* even - every N must have an S. Before I change the article back, can someone point me at an example of an ac induction motor that has an odd number of poles? I can't visualize it... how does the flux get back? If a winding has one end, it has two ends...where's the other end of the winding? --Wtshymanski 22:59, 1 Jun 2005 (UTC)

You're not thinking in "three-phase terms"; in a three-phase world, there's more than a single North and South involved. While it's true that a a) motor must always have a number of poles that is a multiple of the phases and 2) a motor must always have at least two polls, there's no requirement that there be an even number of poles. For example, in my office, I have four different samples of dc brushless motors (which, for operational purposes are really three-phase synchronous motors) and they are all nine-pole motors. (Three of them are small CD-ROM spindle motors and one is a large fractional-horsepower motor from a photocopier.) The use of odd poles is especially common for external-rotor designs where the flux flows through the middle (the merger) of the stationary field coils (as compared to internal-rotor designs where the flux flows through the circumference of the field-coil laminations).
(This has also been discussed on my "talk" page at User talk:Atlant#Electric motor poles.)
Atlant 00:48, 2 Jun 2005 (UTC)
Five and three pole DC-motors on this pic: http://www.floodland.nl/trein/info/digitaal_6_2.jpg --Pjacobi July 4, 2005 18:34 (UTC)

The number of poles is always even... just the number of "physical" poles may not be! This is what's called a "consequent pole motor". You can have a three phase motor with just six physical wound coils in it so they are, say, all North poles. But these types of motors allow more spacing in the iron between the physical poles so the consequent South pole may form between the North poles.--Steve2000 01:49, 28 June 2006 (UTC)Steve2000

In the 1970's or so, there existed a special type of variable-pole lineset generator for computing devices, that would always output the same frequency and voltage regardless of driveshaft speed changes. This was done using a powerful electromagnet to temporaily "imprint" a magnetic field on a spinning ferrous ring, which then moved across an array of pole faces and used the imprinted field to generate power. The number of pole faces and the spacing between them on the spinning ring was constantly variable and would change with each rotation of the ring past the imprinting coil, as the old faces were overwritten with new ones.
This was mentioned in some old issue of Popular Science magazine, so my going back and finding a reference to this is going to be just about impossible. DMahalko 16:35, 30 May 2007 (UTC)

## RPM equation

What about that equation? ${\displaystyle RPM=120F/p}$ works for single phase. Maybe ${\displaystyle RPM=180F/p}$ for three-phase. Meggar 2005 July 4 01:00 (UTC)

No, it's always 120 F/p independant of the number of phases; each phase winding has its own poles (though a winding will have the phase belts overlapping). And the number of poles (in an induction motor) is always even, dag nabit...every N has to have an S! See for example Harold J. Herbein Rotating Machinery (1971),Rinehart Press, San Francisco, or any book on ac motors. --Wtshymanski 4 July 2005 03:22 (UTC)
You can "dag nabit" all you like, but the criterion isn't that a motor must have an even number of poles; the criterion is that for each phase, the (vector?) sum of the various poles contributing to the field produces a north and a south pole aligned through the center of the rotor. The nine-pole external-rotor motors that I've described have no trouble meeting that criterion.
I guess I'll have to get my camera and post a picture. :-)
Atlant 4 July 2005 18:02 (UTC)
Alright, it is always 120F/p. The trick is in how they are counted. A three-phase two-pole motor actually has six poles, but two per phase. That is unless it has three physical poles in which case we imagine the nonexistant ones for the count. Meggar 2005 July 4 18:30 (UTC)

## Few things to add... But where?

Nowhere in this article are cars mentioned. I myself can't do the change since I don't know what kind of electric motors are usually used in cars (but I guess I could find out if anyone already knowledgeable isn't available). Moreso, there are no mentions to new electric motors like this one. Raser Technologies has another high-efficiency motor in production already. --Kim Hokkanen

The usual blower, fan, window, etc. motors in cars are quite standard shunt field or permanent-magnet motors. Cranking motors are series-wound motors. Electric motors have never been the main problem holding back electric cars. It's always been *batteries* - if you could store 10 kWH in something the size and cost of a conventional cranking battery, the IC engine would be a curiosity relegated to aircraft and similar applications. If someone has a lot of good text on automotive propulsion motors,it might well be worth an article by itself, but otherwise I'd like to see the main article as general as possible and not turn into a catalog of motor applications. --Wtshymanski 6 July 2005 17:47 (UTC)
Sounds like we need an "Electric motor applications" sub-article! You've already given us a pretty good outline for the "#Automotive applications" section.
By the way, I think the "shunt field DC motor" is probably nearly dead for auto applications; permanent magnets have just become too powerful for electromagnets to compete. I *THINK* I've even heard that cranking motors now use permanent magnets (but I haven't taken a starting motor apart for a few decades).
Atlant 6 July 2005 21:35 (UTC)
Might be - like I said, I don't know much about these yet. The team in Wales claimed that their motor doesn't have any permanent magnets and very few moving parts. So my question becomes: what kind of motor are they talking about and should it be featured in the article? --Khokkanen 7 July 2005 14:29 (UTC)
I added some material related to motor applications to the motor controller article. I was thinking that material might belong here, but it includes some material that is more appropriate for motor controllers.
C J Cowie 16:33, 6 October 2005 (UTC)

## Thomas Davenport was an American blacksmith and inventor who invented the first DC electrical motor in 1834

This web page indicates that Thomas Davenport invented the first DC electrical motor in 1834. http://chem.ch.huji.ac.il/~eugeniik/history/davenport.html

Thomas Davenport was an American blacksmith and inventor who invented the first DC electrical motor in 1834 and made a small model of electrical railway in 1835. He patented a device for "Improvements in propelling machinery by magnetism and electromagnetism" in 1837 (his electric railway). Davenport used his DC electrical motor to power shop machinery, it was the first practical application for the electric motor. Davenport later started a workshop in New York City and published a journal on electromagnetism.

## DC motor equations

If we've got the equation for speed of an AC motor, why not the equation for the speed of a DC motor? I'd add it myself, but I don't know it. --24.163.161.47 18:36, 20 November 2005 (UTC)

## Planetary Electric Motor?

### Deleted Section

A recent innovation in motor technology has been the development of the Planetary Electric Motor by VibraQ Corporation in Perth, Western Australia.

The technology is designed to deliver a two dimensional planar motion and utilises the fundamental principle of transverse flux where a current carrying conductor within a magnetic field creates thrust. Oscillatory motion is produced through the electric control of the currents and their phasing within the coils.

The Planetary Electric Motor represents an elegant and unique solution to the problem of creating a planar orbital or variable oscillatory motion, without the use of gearboxes or cranks. Motors can be designed to accommodate required application and are easily scaled.

The energy transfer within this technology is controlled through power electronics and therefore is capable of producing different patterns of motion. It uses controlled flow in a magnetic field set up by permanent magnets, which makes the motor inherently more efficient than a conventional rotary motor.

### History

Above section added: November 30, 2005 User:Vidmes

Reverted: December 1, 2005 User:Wtshymanski (rv - PEM image missing, and in bad place, copy sounds spammish and doesn't really explain the concept, plus I've never heard of it except here on Wikipedia.)

What is this exactly? JDR 20:42, 2 December 2005 (UTC)

The web site link does not really explain the concept either and neither does other material (apparently from the same source) that can be found with a Google search. My interpretation is that this is a vibrator that works on the same principle as a tattoo machine or engraving tool. This device appears to add several innovations. It uses both permanent magnets and coils. It uses several magnetic fields and an arrangement for constraining the motion that allows motion in any direction within a plane. The currents in the electromagnets are controlled electronically to cause a pattern of vibratory motion, specifically an orbital motion. The pattern of motion is probably similar to the motion of an orbital wood-finishing sander. Referring to the picture, I suspect that the inner circle moves in an orbital pattern with respect to the outer diameter of the "motor." C J Cowie 01:07, 3 December 2005 (UTC)

## AC motors and DC motors

Could someone split up AC motors and DC motors? This articles is huge! Just wondering. 134.193.26.56 18:48, 30 June 2006 (UTC)

43 kilobytes long : Wikipedia:Article size; > 30 KB May eventually need to be divided (likelihood goes up with size; this is less critical for lists). Thanks. 134.193.26.56 18:50, 30 June 2006 (UTC)

## Torque: current or voltage dependent?

This page says " So what voltage should you operate at? Well, unless you have a battery voltage/current/power limitation, you should operate at 6V. This is simply because DC motors have higher torque at higher voltages."

The article says "Generally speaking the rotational speed of a DC motor is proportional to the voltage applied to it, and the torque is proportional to the current."

Ohm's Law is the problem. A motor coil acts like a resistor, so you cannot increase JUST the voltage. If you increase the voltage across the motor coil, you also increase the current, and that increases the torque. Torque is proportional to current, not to voltage, but because of Ohm's law, current is proportional to voltage. --Wjbeaty 17:51, 4 July 2006 (UTC)
As Wjbeaty says ohms law comes in, a stalled motor driven by DC essentially acts like a resistor with current proportional to voltage. So the higher the voltage the higher the current and the higher the starting torque. Plugwash 16:59, 1 September 2006 (UTC)

Why is saturation mentioned no where??

## Merge

While scanning through new articles, I came across this batch, which have a fair amount of unreferenced information about specific types of motors. It's my opinion that these articles don't have enough information to justify independent notability, so I am recommending a merge:

However, I'll freely admit that I'm not that familiar with the subject matter, so if the regular editors of this page feel that those subjects do deserve independent articles (which can be properly referenced with reliable sources), have at it.  :) --Elonka 22:09, 22 November 2006 (UTC)

The reason for separate pages was by example (see Brushless DC electric motor and because I did not want a major re-write of the electric motor page due to my concerns. It is my oprinion, long describe terms such as Brushless DC motor, etc. have cause consternation in the industry (particularly in todays energy efficient consciousness) because marketing demonstrates the best particulars of the motor core (the Brushless DC motor) without adding the components (and affects) that make the motor core work in a practical installation (such as electronic control). I hope I successfuly brought this out (without a major re-write) for useful evaluation or study by wikipedia format I used: One concern is that all electric motors are AC motors (they need alternating current (or a moving magnetic field) to operate and yet the electric motor page describes DC machines and AC machines, a different. The DC machine term, although prominantly published as a family of motor, describes a motor "system", which is an AC machine core with a means to switch the current (the electromechanical commutator or electronic controller, etc). I made this known in my doubly-fed and singly-fed subjects. Other terms, which are common in motor study but not used in the electric motor page, are "electric machine", which is an electric motor or generator (since any motor can be a generator or visa-versa), and of course, "doubly-fed" and "singly-fed", which are two categories that all electric machines fall into. [Of course, I have seen terms such as families, types, etc., as well, rather than "category", but I also have seen these terms to differentiate induction motors from synchronous motors, etc. So the term "category" is satisfactory?] Although the concept of a "truly" doubly-fed machine has been around since day one (doubly-fed machines are the classic study), advances in electronic control have made these machines realistic: so I tried to indirectly update the electric motor page with this information. For instance, the electric motor page has a Wound-rotor electric AC motor subject, but this is a singly-fed (induction) machine, which should not be confused with the doubly-fed (wound-rotor) machine (another page) that shows significant attributes for cost, efficiency, and size. Fklatt 14:59, 23 November 2006 (UTC)

I would like to add that I am new to wikipedia and I am just learning wikipedia's editing and contribution protocol, which I hope I haven't violated (past, present, or future). Fklatt 15:05, 23 November 2006 (UTC)

## cillia motors

does anyone think there should be a part on bilogical cillia motor, or flagella motors, they appear to have all motor part, and since nano motor is here it seems to be a missing part of this article —The preceding JUBALCAIN 00:39, 28 January 2007 (UTC)

## Perpetual motion machines

quote from "AC motors":

The total energy supplied to operate the device equaled the sum of the energy expended in the armature and field coils. The power developed in operation of the device equaled the product of the energy expended in the armature and field coils.

If that statement has any reasonable interpretation, it needs to be explained at greater length, because it appears to describe a perpetual motion machine, which electric motors are not widely known to be.

It doesn't even make any sense from the point of view of dimensional analysis, let alone the law of conservation of energy. Power is defined as energy flow per unit time, not energy squared.

And thanks for just deleting my edit where I tried to point out how nonsensical this was. When people identify obvious mistakes, just pretend it never happened. That's the best way to get quality content. —The preceding unsigned comment was added by 24.82.87.182 (talkcontribs).

I have to say I agree with the above editor (though the way to raise the issue is not to add a comment in the text of the article itself). What exactly does the statement quoted above purport to mean? I'll give it a day, and then remove the text and the accompanying table from the article. — BillC talk 17:32, 20 February 2007 (UTC)
24.82.87.182, the way to get quality content is either for you to be bold and correct the content or to raise issues on the article's talk page (here). Simply putting an editorial comment into the article (with no "Edit summary" provided by you, BTW) is likely to only get your edit reverted (as I and another editor did yours).
Atlant 17:51, 20 February 2007 (UTC)
I've now removed the material, including the table. The editor(s) who added it had clearly been working from the text of Tesla's Letter Patent 416194. However, there was at least one error of transcription, and an error of understanding. The latter patent indeed says that the energy supplied to the motor is equal to the sum of the energies in the armature and field. However, it says that the power supplied is proportional to the product of both, not equal to it. What Tesla is getting at, and says more directly later in the same letter, is that the induction motor operates at its peak efficiency when the iron loss and copper loss are equal. — BillC talk 01:51, 21 February 2007 (UTC)

## Translation help for an electric motor

I'm trying to find an equivalant to the German article de:Drehstrom-Asynchronmotor - literal translation would be three-phase asynchronous motor. I tend towards variable-frequency drive, but I'm confused that the article makes no mention of electric locomotives and calls power outputs of 5,000 hp or above unusual, while Drehstrom-Asynchronmotoren have been standard in German-built locomotives for 25-30 years and are often rated for 6,400 kW (8,600 hp) cf. DB Class 120, DBAG Class 101, TRAXX etc.

Can anybody with technical knowledge clear this up? --84.44.217.214 15:40, 27 February 2007 (UTC)

An "asynchronous" motor is almost certainly what we would call in English an "induction motor". The key is that the rotor turns somewhat asynchronously with the rotating magnetic field (and, in doing so, electric current is induced into the rotor windings). A VFD is an increasingly-common drive scheme for variable-speed induction motors but is not absolutely necessary.
Atlant 17:20, 27 February 2007 (UTC)
Would the presence of a frequency changer be an indication towards VFD? Translated from de:DB Baureihe 120: The frequency changers output three-phase AC of variable current (0-2000 V) and frequency (0.4-120 Hz) to the traction motors (section "Die elektrische Ausrüstung") --84.44.217.214 18:14, 27 February 2007 (UTC)
Even more confusion after actually reading the article instead of skimming it: The section "Wound Rotor" reads:
Carbon brushes connect the slip rings to an external controller such as a variable resistor that allows changing the motor's slip rate. [...] Transistorized inverters with variable-frequency drive can now be used for speed control, and wound rotor motors are becoming less common. [...] This type of motor is becoming more common in traction applications such as locomotives, where it is known as the asynchronous traction motor.
From what I read in the German-language articles, the advantage of the asynchronous motor is its lack of carbon brushes, making it very low-maintenance. I also read about the progress in asynchronous motors being the switch from GTOs to IGBTs which contradicts "Wound Rotor = three-phase asynchronous"
One correction to my earlier post (should've logged in): Modern locomotives usually have four traction motors, so each one's power output would be around 1,600 kW.
Perhaps I should add that one argument against introducing the TGV in Germany was its use of the "outdated synchronous motor" - and indeed, 20 years later the SNCF TGV POS is the first TGV to use asynchronous motors ;-) --Qualle (talk) 22:18, 27 February 2007 (UTC)

Block quote

A wound rotor was traditionally used for speed control (before inverters became common), I believe, by externally changing the winding impedance, which necessitated slip ring contacts and brushes. What the article is referring to is a squirrel-cage type rotor, which is more efficient. Both are asynchronous induction motors. Choppingmall 23:48, 24 August 2007 (UTC)

## Really, really long!

I believe the article is too long. I was here to search for a simple info and I was a bit puzzled. I would say that even the TOC could be reorganized. Could you please consider a split? Personally, I propose to keep the "common" concepts here, split AC from DC and the nanotech version. Starters may also go elsewhere but I'm not sure. I'm not really skilled in this stuff so I leave the decision to people more involved with "power" devices and such... Thank you!
MaxDZ8 talk 19:33, 20 May 2007 (UTC)

Ofcourse the article is very long. Moreover AC motor, DC motor, Induction motor, Synchronous motor all should have seperate articles. I think we should not discuss any details of these stuffs in this articles. Rather just classify the electric motor and leave to write descriptions in seperate articles. Most important point is, English Wikipedia has very poor collection of informations as regards the Electrical machinr or power generation and transmission. Articles should be more Effective. I am trying to write in this aspect. Please shorten this article and consider to write in seperate articles. It's ernest request. All the students of Electrical engineeing feel that Wikipedia cannot help them. So we need to do sth. -- Hermitage17 06:19, 21 June 2007 (UTC)
Deleting a large amount of content will not fix the problem. If you are serious about this pleace consider a split ( as previously suggested) and then replacing the section in the article with a paragraph or so to give general overview of each type of motor. What you replaced it with was of no use to a reader. Please discuss any future changes here before large edits. Happy trails :: maelgwn :: talk 06:39, 21 June 2007 (UTC)
Ok so the AC section has been split to AC motor but could do with some clean up. Sorry i dont have the time atm :: maelgwn :: talk 06:59, 21 June 2007 (UTC)

## how do you reverse the 1 hp motor?

It depends what type of motor it is. 86.21.225.104 15:37, 6 September 2007 (UTC)

## Rewrite

The article needs a comb-out - why have we lost the good illustration of the DC motor? Why all the non-encylopediac pontificating? Windy and pompous is not my favorite thing to read. Fragmenting core concepts off to other articles while leaving in trivia (ball-bearing motors, forsooth!) is not the way to grow an encyclopedia. I'd start fixing this now but time is short. --Wtshymanski 16:12, 19 August 2007 (UTC)

There has been clamoring to better organize the article, as it has grown too long in the tooth. I have thusly promoted the DC Motor section to its own entry. I remind you that the article is "Electric Motors", not "Common Electric Motors" or even "Useful Electric Motors". It is a broad topic, encompassing a fabulous plethora of mechanisms, many of great utility, and others not. Choppingmall 07:10, 21 August 2007 (UTC)

## Motor dimensioning

Dimensioning an electric motor requires knowledge about mechanical, electrical and thermal aspects. It is not straight-forward and has some cavaets that need to be avoided. I think it would enhance the Wikipedia if there was information on this available (most people look up Electric Motor because they want to know what type and kind to use I think). I am willing to contribute about this because of my experience, but where and how should it fit in the Wikipedia and are there people that are willing to support this? Before I make the effort, anybody have suggestions / tips? (Motor Expert (talk) 18:19, 13 December 2007 (UTC))

Thank you for your offer. A brief discussion of what the main theoretical issues are might be appropriate, but only if you gave sufficient citations to reliable sources, such as published books or academic journals. However, giving practical advice or recommendations on how to choose a motor would not be appropriate. Wikipedia is not a guide or a textbook (this policy is described here). Also, adding a link to your own website as a reference would be unacceptable as self-promotion per the Wikipedia policy WP:SPAM (as explained to you by other editors when reverting your previous edits [2][3][4][5]) and also possibly as a conflict of interest per WP:COI. - Neparis (talk) 19:18, 29 December 2007 (UTC)

## Page Organization / Terms

This article uses many terms which should probably be defined or referenced before using them such as: field wound motor, series wound motor... There is a lot of discussion of technical details of various motors and equations, but there is not a good overview of the types of motors and how they can be characterized. Maybe the various motor types should be split out onto separate pages? --Martin

Commutation is one of these. It doesn't have its own article, apparently, at least in the context of electricity. Closest I found is Commutator (electric). Maybe we should like to that on first use? --Treekids (talk) 23:52, 8 January 2008 (UTC)

## Spam

A link to electojects.com has been repeatedly added to Stepper motor, Electric motor and Brushless DC electric motor by Special:Contributions/217.53.109.235, Special:Contributions/82.201.156.201, Special:Contributions/217.53.107.168, Special:Contributions/217.53.16.164, and others.

The link in question is registered to Abdoh Ali Mohamed, Hay Swesri, Nasr City, Cairo, Egypt.[6]

I wonder if the four IP addresses listed above have any connection... Naw, couldn't be. [7][8][9][10] Egypt is a big country. Must be a coincidence.

I'm going to start patrolling wikipedia for any links to electojects.com or redirects to it and deleting them on sight. If they come back, I'll move to blacklist the address. Mdsummermsw (talk) 18:06, 28 December 2007 (UTC)

See Talk:Stepper_motor#Spam. - Mdsummermsw (talk) 19:58, 28 December 2007 (UTC)

The tide is coming in from Egypt:
62.135.41.144 ([11][12])
62.135.41.205 ([13][14])
62.135.41.231 ([15][16])
62.139.238.152 ([17])
82.201.156.201 ([18][19][20])
213.212.221.17 ([21][22])
217.53.18.231 ([23][24])
196.205.192.27 ([25])
As you might have guessed, all registered in Egypt.
2. elect.awardspace.com/stepper/ spam by
41.232.178.243 ([26])
62.135.24.250 ([27])
82.201.156.179 ([28])
217.53.136.129 ([29])
all registered in Egypt
3. 1lo.info/stepping spam by
82.201.156.111 ([30])
82.201.156.99 ([31])
217.53.16.168 ([32][33])
217.53.16.133([34])
84.36.187.95 ([35]) all registered in Egypt
Not known, except for the IP:
1. www.specamotor.com spam by:
User:Motor_Expert ([36][37][38])
194.105.120.80 ([39][40]) registered in Netherlands
2. stepper-motor.blogspot.com spam by
User:Pejuang ([41][42][43])
With supreme irony, 62.139.238.152 has complained to admin User:ABCD "We need some admin help here".
I think I can smell a few socks here. - Neparis (talk) 23:20, 30 December 2007 (UTC)
Please also see Talk:Stepper_motor#Spam. - Mdsummermsw (talk) 13:30, 31 December 2007 (UTC)
Footnote: the identified problem domains have now been spam blacklisted.[44] - Neparis (talk) 20:39, 24 January 2008 (UTC)
The spammer is back again, this time using a url hiding service smileurl.com to obfuscate a redirect to elect.awardspace.com/stepper. 62.135.24.250 is registered in Egypt. I have added this new IP to the above list. - Neparis (talk) 04:46, 3 February 2008 (UTC)
Added another spamming IP 217.53.136.129 to the list above. - Neparis (talk) 04:20, 4 February 2008 (UTC)
Yet another IP from Egypt is spamming elect.awardspace.com/stepper using smileurl.com. This is really getting out of hand. I've updated the list above, and propose to create a Category:Suspected Wikipedia sockpuppets of 82.201.156.201 (targeting 82.201.156.201 because it is the most prolific). - Neparis (talk) 05:53, 19 February 2008 (UTC)

## Low Temperature Stirling Engine

I would like to know if it is fessable to run an electric turbine from the low temperature Sterling Engine, the folowing will give an out line (and I meen a full working unit to produce Electricaty ,Not a toy)

The Kontax Low Temperature Differential Stirling Engine is an excellent demonstration of a heat engine, showing with one spin of the flywheel a clean and simple way of converting thermal energy into motion. This engine will operate from many heat sources, including hot water, computer monitor, TV and the human hand. As long as there is a small difference in temperature between the upper and lower plates this engine will run.

Every assembled engine has been tested to run off the heat of a hand.

This engine has been meticulously engineered. As any Stirling Engine enthusiast knows, friction is your enemy in LTD models. With this in mind, all potential sources of friction in this engine have been eliminated. Another common problem with LTD Stirlings is heat transfer between the plates. Again, all possible routes for heat to transfer directly between the plates have been eliminated.

Based on the pioneering work done by Dr Senft at the University of Wisconsin, this model has been engineered in England, manufactured in England using hi-tech CNC equipment, and is sold from England.

A large number of schools and universities have bought our engines for educational use, the transparent chamber and cylinder make it very easy to explain the Stirling cycle to students. Many of our engines have been kept running for years on top of coffee machines, computers, fax machines, etc. in shops, kitchens and offices all over the world. Many customers take great delight in running our engines on a bowl of ice or snow, where the engine happily runs, but backwards.

Engine features:-

Low-profile heat insulating chamber pillars, giving good surface contact with heat source Aluminium main pillar, hub & spokes All airtight seals are made with high strength precision screw threads and nitrile O rings Both connecting rods are positively located using low friction PET and stainless screws Micron precision Borosilicate glass cylinder and Graphite power piston, the best combination Ultra low friction demagnetised and degreased bearings, NO lubrication required Fully CNC machined, ensuring crisp, clean tidy edges all over Engine parts ultrasonically cleaned before hand assembly Precision engineered and hand built in England Engraved it with the KONTAX name Major dimensions:-

Base plates - 92mm diameter, 2mm thick Flywheel - 82mm diameter, 4mm thick Power piston - 9.5mm tube diameter Displacer - 70mm diameter, 8mm thick Overall height - 120mm For more information please download our pdf files:

Operation instructions.pdf Stirling engine how it works.pdf Stirling engine history.pdf

All our pdf fact sheets are available on the videos page.

## Comment

I work for a company that uses deep freezers's I need this taken to a bigger working model

Q/ Is it posible? —Preceding unsigned comment added by Anglosaxonmix118 (talkcontribs) 12:51, 29 April 2008 (UTC)

## Table

new table:

AC Induction
Least expensive
Long life
high power
Rotation slips from frequency
Low starting torque
Fans Uni/Poly-phase AC
AC Induction
(split-phase capacitor)
High power
high starting torque
Rotation slips from frequency Appliances Uni/Poly-phase AC
AC Synchronous Rotation in-sync with freq
long-life (alternator)
More expensive Clocks
Audio turntables
tape drives
Uni/Poly-phase AC
Stepper DC Precision positioning
High holding torque
Slow speed
Requires a controller
Positioning in printers and floppy drives Multiphase DC
Brushless DC Long lifespan
low maintenance
High efficiency
High initial cost
Requires a controller
Hard drives
CD/DVD players
electric vehicles
Multiphase DC
Brushed (PM) DC Low initial cost
Simple speed control (Dynamo)
High maintenance (brushes)
Low lifespan
automotive starters
Direct (PWM)

I believe Brushless and Brushed DC should be reversed. Brushless DC requires PWM for it's control. —Preceding unsigned comment added by 221.113.184.22 (talk) 08:44, 9 October 2008 (UTC)

--Mikiemike (talk) 22:30, 22 July 2008 (UTC)

## 1Motor types, Spherical 2. Type, application , efficiency, weight charts

What is Spherical Motor? Is it too new to be in this 'vital' article? I need an outsider-to-inside look. Otherwise the printed materials on electric motors are either academic or trade inside opinions. 67.86.58.205 (talk) 01:39, 23 June 2008 (UTC)Wikici.

## super conductive motors? Should article mention about them?

Hello,

I read that in Japan tests have been made for super conductive motors. http://www.pinktentacle.com/2008/06/superconductor-electric-vehicle/

Is this just some kind of hype or is someone really making this kind of tests? If it is real, should the article mention someting about futuristic technology /cut of the edge technology? —Preceding unsigned comment added by 213.28.144.2 (talk) 07:34, 10 October 2008 (UTC)

## Jedlik, 1828

You know...?

Electric car http://www.epa.oszk.hu/00700/00775/00027/abra176.jpg 1828 <===IT WORKS —Preceding unsigned comment added by 89.223.192.89 (talk) 06:13, 10 August 2008 (UTC)

gg630504

Hahaha, Hungary isn't eastern european country. It's a Central European country as Germany Switzerland Austria Czech Polnad etc... Eastern european = eastern orthodox culture.—Preceding unsigned comment added by 89.223.192.89 (talkcontribs)

The only English that pops up on the above link is 404 Not found. I've been skimming over the Net for the last hour trying to find a good description of what it was Jedlick built in 1828. There's a powerful lot of Hungarian nationalism out there ( and the usual Eastern European debate about what nationality anyone notable really was) but no technical description. Was it a table-top lecture hall demonstration or did Jedlik pump water, saw wood, print newspapers or apply his motor to any other practical application, even if dissolving zinc plates in acid made the energy cost ruinously high? References would be good (in English!).
I'm fascinated by these 1820's guys trying to turn lecture-hall stunts into something that could do real work - it must have seemed like magic to the odd visitor to the workshops, to see metal bits come to life without steam or wind or someone turning a crank - and the whole electochemical apparatus would have been obscure and mysterious to an 1820's observer. Though Jedlik must have been better off in experimental physics, the fact that he's relatively as obscure as Davenport and Sturgeon indicates that these men were all ahead of the time. This is a great story and needs to be on Wikipedia but needs a lot more research - for some things Google isn't good enough. --Wtshymanski (talk) 17:35, 7 June 2008 (UTC)
I question the correctness of making the assertion in this article that Jedlik invented the electric motor or that he invented the electric car in 1828. Do reliable secondary sources on the history of electrical technology credit Jedlik with this invention? Books I have seen on the history of electric motors give the credit for early developments to others, who gave well documented demonstrations, such as Davenport, 1837. Did he publicly demonstrate it in 1828 and was it written up in scientific journals of that year, or did he state decades later that he had invented such a device? Is the model in the photo known to have been built by Jedlik in 1828, or is it a reconstruction made many years later for museum exhibit?The article Ányos Jedlik does not inspire much confidence, since it provides little documentation of early public demonstrations or of publications in 1828. It implies thqt he only wrote about his early electrical experiments in the 1850's. See [45] pp306-321 for a history of electric motors written in 1888, which gives the chronology of invention and improvement about the same as in reliable histories of the subject today. By giving all credit to Jedlik, Wikipedia violates RS and WP:NPOV. Edison (talk) 18:31, 23 December 2008 (UTC)

That's the problem with wikipedia, the uneducated or half-educated users/editors. Ányos Jedlik's invention is well known for university professors, but there are some common people who want to negate the facts. ridiculous(talk)—Preceding unsigned comment added by 77.111.185.112 (talkcontribs) (Editing as Celebration1981)

English language was not important European language in the XIX century. The most important scientific language was Latin German and French. Sorry, Jedlik spoke only Hungarian Latin German and French. Very few foreigner people could speak English that time. The US wasn't important scientific place before 1945. Look the Nobel awards: Until this day, 80% of "American" scientists were not born and educated in US, so they are not real "American" inventors/scientists. Therefore Americans have one of the worst Nobel awards / population ratio in civilized world. Ányos Jedlik was an university professor with much more knowledge than your cowboy:)) Hungary has the oldest University of Technology in the world ==> Budapest University of Technology and Economics. Hi was editor and writer of periodical: "Zeitschrift für Physik und Mathematik" I'm sorry, your cowboy Davenport was just a secondary or a later inventor, his invention was 9 years later (1837) . —Preceding unsigned comment added by 77.111.185.112 (talk) 08:33, 25 December 2008 (UTC)

The first electric-engine of the world will be presented at the exhibition, made by a Hungarian engineer-physician Ányos Jedlik, who became member of the Hungarian Academy simultaneously with Faraday, the other famous expert of electricity. The works of Jedlik were even recognised by Siemens, who worked on similar fields. The Jedlik-relic was already presented in 1927 at the celebration of the 100th anniversary of Volta’s death expert of electronics, who received it with great satisfaction. At that time, Jedlik's engine was already 100 years old.

Sorry the real electric motor, first real transformer,patent of the first electronic television (Kálmán Tihanyi are not American inventions, but Hungarian. --Celebration1981 (talk) 16:57, 6 April 2009 (UTC)

It is hard to take seriously a contributor who prefaces his contribution with "HAHAHAHA." The webpage does not provide any reference to primary sources documenting that Jedlik published anything about the motor in 1827 or that he publicly exhibited it. For all we know, it was constructed in 1927 as an illustration. What is its provenance prior to 1927? The webpage also does not cite any publication from 1927 to verify the claim that it was exhibited then or that it was documented to be 100 years old at that time. When was it first illustrated and described in a book or scientific publication? In histories of electricity and of electric motors from the 1880's no mention was made of it, which is surprising given that several other experimenters such as Faraday, Barlow, and Davenport had demonstrated motors in the 1830's which were well documented. Edison (talk) 15:07, 8 April 2009 (UTC)

Can you read? Read again the text. The verb "presented (donate)" and the verb "construct" are not the same! This device was constructed in 1827, and it was presented/donated in 1927. —Preceding unsigned comment added by 77.111.185.112 (talk) 10:27, 9 April 2009 (UTC) Faraday's device or or Barlow's device is not considered as motors. They are demonstrator devices, wich showed that electric energy is transformable to mechanic energy. It's a very very farfetched thing to call this devices as motors. Read about jedlik inventions:(Encyclopaedia Britannica, 1961). In the countries of >>>Continental Europe<< the old books of history of technology didn't know Davenport's name, but Jedlik is considered as inventor of electric motor. Davenports's name is less-known name in Continental Europe. Until this day, most americans belive that automobile and spaceship is american invention, wich is laughable. You are one of them. —Preceding unsigned comment added by 77.111.185.112 (talk) 10:19, 9 April 2009 (UTC)

But Thomas Davenport is less known inventor/person on the internet too. Type in google: "thomas Davenport 57,300 and type Jedlik 227,000. MY American nationalist friend, you fight for a looser affair.—Preceding unsigned comment added by 77.111.185.112 (talkcontribs)

## Plagiarism

What is the Wikipedia's policy on plagiarism? The first paragraph of the Materials section is copied straight from http://dic.academic.ru/dic.nsf/enwiki/4271125 and the actual references not added to the page. Doesn't Wikipedia lose credibility if it appears to be made up of stolen work? Kevinharbin (talk) 18:42, 22 January 2009 (UTC)

The site is an acknowledge mirror of Wikipedia. --Old Moonraker (talk) 18:47, 22 January 2009 (UTC)
Looks at first sight like they've copied from us. That's not illegal, but they're supposed to reference us. That citeweb stuff is a bit of a giveaway I would have thought.- (User) Wolfkeeper (Talk) 18:50, 22 January 2009 (UTC)
They're not properly compliant, but there's a small link to WP top right of their article.--Old Moonraker (talk) 09:26, 23 January 2009 (UTC)

## Efficiency?

howzabout a few words about efficiency, heat loss, etc.? —Preceding unsigned comment added by 68.80.95.189 (talk) 00:06, 4 March 2009 (UTC)

## Specific query

Ever since I played with synchros in high school in the early 1950s, and learned about synchro differentials in the Navy (1954), I have wondered about modifying/redesigning a differential synchro for high speed, and connecting both rotor and stator to a three-phase power source. Would it run (if properly connected) at 7,200 rpm on 60 Hz? The short paragraph on doubly-fed motors (totally new to me!) was tantalizing, but still leaves me wondering. Are such motors similar to differential synchros? Best regards, and TIA! Nikevich (talk) 21:31, 21 April 2009 (UTC)

## Confusing wording

Under singly-fed motors, I read "Singly-fed electric machines have an effective constant torque speed range up to synchronous speed for a given excitation frequency." Just what does "constant torque speed range" mean? Afaik, the torque varies considerably with speed; typical starting torque is fairly low, and drops off as the motor approaches synch. speed. Torque is surely not invariant with speed! Regards, Nikevich (talk) 02:28, 22 April 2009 (UTC)

## American nationalism & vandalism by "Edison" USER

It's a craziness. "Edison" forces a less known inventor: the cowboy Davenport. Jedlik is far more known inventor in European Continent, and in European universities. Museums have a lot of old demonstrative devices contemporary correspondences with other scientists and students. They are less than 200 years old proofs. Therefore the Carbon-14 researches could determine the extremly correct age of this letters and devices. The question is if we are going to write an encyclopedia based on real facts or simply on what everybody remembers from his local (often not particularly good) school. I believe what the really good encyclopedia describes the world and its history as they are and not local teacher's opinion. This nationalism must be reverted. —Preceding unsigned comment added by Celebration1981 (talkcontribs) 05:49, 4 May 2009 (UTC)

First, you are making a personal attack on someone and you really must not do this. Wikipedia has a definition of vandalism at WP:VANDALISM and there is no vandalism going on here.
Secondly, we have a policy about the sources we expect to be used at WP:RELIABLE, and if you read WP:SPS you will also see that normally we don't allow self-published sources. The author of the book Made in Hungary is also the publisher, see [46]. The website of a bookfair is also not a reliable source. Dougweller (talk) 08:49, 4 May 2009 (UTC)

Haha "edison' try to suggest that "Hungarian writers assert that" (his sentences contains lot of injurious sceptic keynote) It must be rewrite to European because "edison's" favourite american Davenport is less known than Jedlik in Europe. He can't tolerate that Jedlik was the first inventor and Davenport's ivention is 4-5 years latter. It might Davenport's invention was the first in USA in 1837, but Jedlik was the first on this planet in 1827 --Celebration1981 (talk) 09:40, 4 May 2009 (UTC)

I hope that if you think about it, you will see the problem that we English-speaking editors face. On one hand, we know that there is a long history of people making bogus claims that somebody from their country was the first to do something, so we have to be careful about checking things like that, and can't simply trust editors who add such information, especially if they come from that country. On the other hand, we don't speak Hungarian, and can't read sources written in Hungarian. We are not trying to be hostile, we simply want to see proper evidence that we can actually check. Looie496 (talk) 16:12, 4 May 2009 (UTC)

Hahaha, English wikipedia doesn't belongs to USA only. There are a lot of other English speaking countries. Please learn French German or Latin, thus you will go farther in old history of technology. --Celebration1981 (talk) 16:53, 4 May 2009 (UTC)

You aren't listening, so let me be clear. When one editor fights against many editors, the one editor always loses. If you don't try to cooperate, you won't accomplish anything. Are you going to make some effort to cooperate, or must we simply revert all your edits? Looie496 (talk) 18:03, 4 May 2009 (UTC)

--Celebration1981 (talk) 06:01, 6 May 2009 (UTC)

Lots of Yahoo and German Wikipedia type answers, which count for nothing in terms of reliability. Any reliable sources you wish to point out amongst the Google search results? Edison (talk) 18:24, 6 May 2009 (UTC)

You forget the sites of universities, and world's oldest electro-techonology book (printed in 1850's, München) stated that anyos jedlik was the first constructor of real electic motors: http://aquarium.teufel100.de/?p=270

http://www.technik-geraete.de/w/elektro-motor.html Als erster echter Elektro-Motor ist der des Ungarn Ányos Jedlik in die Geschichtsbücher eingegangen.

http://science.orf.at/science/news/9002 Auf der Ausstellung wird auch der erste Elektromotor der Weltgeschichte zu sehen, der vom ungarischen Ingeneur Ányos Jedlik konstruiert wurde http://www.buod.de/Docs/ungarn.pdf ersten, funktionierenden Elektromotor, 18 Jahre vor Siemens und 1861 den .... ergangen wie den Ányos Jedlik

I speak German too, although not all that well. The only one of these that contains much information is the uni-linz article, which looks like a nice review, and perhaps is a preprint. It says that the first electric motors came from Barlow, Ritchie, and Jedlik, with Barlow's the earliest, although it was very primitive. Jedlik's 1827 version was distinguished from the others by use of an electromagnet (solenoid) rather than a permanent magnet. None of these were capable of doing any work -- the first functional motor came from Jacobi in 1835. Looie496 (talk) 20:07, 6 May 2009 (UTC)

## Jedlik images

I don't object to a picture of the Jedlik motor at this point, but I don't think there is a need for more than one, and the middle one looks like the best. I removed the other two yesterday, but was reverted. On the principle of not edit-warring, could I ask for input from other editors about the right thing to do here? Looie496 (talk) 14:28, 5 May 2009 (UTC)

If there were convincing proof that they were what the labels say they are, and as old as they are claimed to be, more than one might be appropriate. But I have been unable to get the poster of the images to satisfy repeated requests for proof that they were actually built by Jedlik in 1827 or 1828. They are presented as "evidence" that he "invented the electric motor," a claim that has little support from histories of 19th century electrical science, at least those not from Hungary. Editors able to read technical article in Hungarian should check the refs at the Jedlik article and see what 20th century scholars say, and see what public demonstrations were made or what scientific writings by Jedlik described his motor before, say, the 1860's. I am concerned thet the motors might be illustrative models made in the 20th or late 19th century, reflecting inventions and improvements by many other 19th century inventors, rather than 1820's prototypes. Edison (talk) 00:06, 6 May 2009 (UTC)

## "Ányos Jedlik started experimenting with electromagnetic rotating device" fails verification

European writers assert that in 1827, Hungarian Ányos Jedlik started experimenting with electromagnetic rotating devices had been marked with a {{who}} tag, but this has been twice removed. A reference to "Britannica 1961" now adorns the claim. I have in turn attached a {{Failed verification}} tag, partly because the "European writers" still haven't been named and partly because, although I don't have access to Britannica 1961, I have checked the 1998, 2004 and 2009 (online) edition and he's not in any of them. Clarification, naming the writers and their works, please! --Old Moonraker (talk) 14:47, 7 May 2009 (UTC)

The key question is, when was this alleged experimentation published in a scientific journal or book so that it came to the attention of other scientists and experimenters? It is easy to write 40 or 100 years later that someone "invented" things. The work of several other electric motor inventors or experimenters is easily verified, such as Faraday, Sturgeon, Davenport, Pixii, Farmer, Edison and Siemens, to name a few. We need scholarly secondary sources about Jedlik, which cite his original publications and documented public demonstrations. Editors who can read any references in Hungarian at the Jedlik article would be very helpful in evaluating whether the claims for Jedlik's priority are verifiable. Edison (talk) 05:21, 8 May 2009 (UTC)
1998 2004 2009 versions of Britannica didn't contain history of inventions. Therefore I suggest look the older versions (forexample 1961 version). In the 1961 version of Britannica had an own article about Jedlik.
HAHAHA "It is easy to write 40 or 100 years later that someone "invented" things." Jedlik teached between 1826-34 in three universities (this universities had polish austrian german hungarian czech etc... students), which represented a wider public that time than a special publication for a sicentific newspaper in western europe. That time, a typical "great" scientific articles or books were printed in 100 or maximum 300 impression in Europe or US. Therefore, it was a better to show your invention for the masses.—Preceding unsigned comment added by Celebration1981 (talkcontribs)
A claim that Jedlik "teached between 1826-34 in three universities" in no way verifies that he showed his students the motor in the illustrations you have added to articles, or that he had at that time invented a motor with electromagnets in the rotor and field windings, or with a commutator. What are the earliest publications? And Britannica in recent editions most certainly contains histories of inventions, just as it did in editions long before 1961, when it credited people other than Jedlik with all the discoveries you attribute to him, just as other reliable scholarly works on the history of electrical technology did. Wikipedia should reflect the consensus of scholarly opinion, and not be a forum to present historical claims that are out of the mainstream as established fact. Thanks. Edison (talk) 03:19, 10 May 2009 (UTC)
I could find no mention of Jedlik in the 1911 Britannica. But they do give credit to Faraday, Sturgeon, Pixii, Siemens, Gramme, Pacinotti and others for developments in rotating electrical machines. If Jedlik "invented the electric motor" then 19th century histories of electric motors should have mentioned his contribution. To the contrary, in "The electric motor and its applications," by Thomas C. Martin (1891) there is no mention of Jedlik, but credit is given ("Chapter 2: Early motors and experiments in Europe") to Jacobi, Barlow, Pacinotti, Gramme and others. Chapter 3, "Early motors and experiments in America" describes the work of Davenport and others. It seems to violate WP:NPOV and WP:UNDUE to have this and numerous other articles assert that Jedlik "invented the electric motor" without better independent and reliable sources. Edison (talk) 03:33, 10 May 2009 (UTC)
Jedlik was still too little known in 1905 to be mentioned in the detailed history of the early development of electric motors in Edwin Houston's 1905 "Electricity in everyday life," which also credits the usually cited inventors and advancers of electric motor technology, in Chapter XXVIII "Early history of the electric motor" pages 387-409. Edison (talk) 04:15, 10 May 2009 (UTC)

Electricity and magnetism, translated from the French of Amédée Guillemin. Rev. and ed. by Silvanus P. Thompson. London, MacMillan, 1891 AND: Nature 53. (printed in 1896) page: 516

Check wiki article "Jedlik's dynamo" list of refs .Wdl1961 (talk) 15:09, 23 September 2009 (UTC)