Talk:Electric motor

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Old threads moved to archive[edit]

The talk page was getting quite long even by modern Wikipedia standards. The older threads are at Talk:Electric motor/Archive 1 --Wtshymanski (talk) 21:47, 15 October 2009 (UTC)

DC series motor[edit]

There are four types of DC motor:

  • DC series motor
  • DC shunt motor
  • DC compound motor -
    • there are also two types:
    • cumulative compound
    • differentially compounded
  • Permanent Magnet DC Motor

any coverage of this in wiki???

Wdl1961 (talk) 13:57, 5 July 2009 (UTC)

Split off history[edit]

We have proponents of what other consider to be minor figures insisting that they get space in the history section. A possible solution: Create a new history article where there is room for every minor figure, and trim the history section here to be very short.Ccrrccrr (talk) 12:50, 16 August 2009 (UTC)

A question about magnetic fields in a motor[edit]

Since we are taught that in general, the magnetic field B from a simple coil of wire is the turns of wire times both current and permeability of its core, over the its height and diameter, then voltage doesn't really play any role in the flux created to drive the motor, is this partly right? Else the formula should also have included the voltage as a component of the flux density, but that is not the case. --Nabo0o (talk) 18:16, 4 October 2009 (UTC)

So I guess what my question really is: Do motors only need amps and not watts to create motion, since voltage isn't included in the magnetic flux density formula? --Nabo0o (talk) 00:28, 5 October 2009 (UTC)

This page is for discussion of the article, not of motors. If you have a question about motors, you can go to the reference desk (WP:refdesk). On the other hand, if there is a part of this article that you think is unclear, you could point that out here. Ccrrccrr (talk) 00:40, 5 October 2009 (UTC)
Sorry, I guess biggest reason I asked was to know it myself. But then again, maybe the reader should also be allowed to understand the result of that formula, if it is watts or amps that is powering our electric motors. Do you have any opinion on this? Thanks! --Nabo0o (talk) 08:45, 5 October 2009 (UTC)
You'd have to be more specific about what section paragraph in the article you think needs improvement for me to know how to respond.Ccrrccrr (talk) 13:33, 5 October 2009 (UTC)
Voltage is needed to overcome the resistance of the wires, the self-inductance of the coil and mutual inductance of other coils and of permanent magnets. Conservation of energy tells that the watts in must be at least as large as the watts out. This is probably too late to help the one with the queston. David R. Ingham (talk) 20:06, 25 November 2010 (UTC)

Well, one could discusss the back-EMF, which is the connection between the power output from the motor and the power drawn from the electrical input. The similar connection between the secondary and primary on transformers also exists. Gah4 (talk) 00:22, 25 January 2011 (UTC)


Ubiquitous with perspicacity i understood. it is not used much in n/a by engineers. many non native english users look at wikpedia . these were the reasons i changed it to widespread. Wdl1961 (talk) 13:51, 15 October 2009 (UTC)

Hi Wdl1961. There are two good reasons for using ubiquitous. First, the meaning matches perfectly what is meant here - that electric motors are much more than widespread, they are so common as to be unnoticed. One could perhaps use pervasive or universal in its place, but neither of those quite fit either. Second, its use is not rare - it is actually used reasonably widely (for instance - ubiquitous computing). If you were objecting to something like celerity (or even perspicacity), then I wouldn't hesitate to agree with you. But ubiquitous? Even using a very hand waving argument, google returns 10million hits for ubiquitous, 35million for widespread - which is to say, their use (on the net at least) is roughly the same. Lissajous (talk) 15:37, 15 October 2009 (UTC)
Hi Lissajous. it was not meant to be critical and mostly my problem. keep up the good work. Wdl1961 (talk) 19:12, 15 October 2009 (UTC)
Ack. Lissajous (talk) 20:41, 15 October 2009 (UTC)

Efficiency of motors[edit]

I modified the efficiency section because it was wrong, and inconsistent with the "implications" section that followed it. For a DC motor, at least, the efficiency of the motor peaks at < 1/2 the stall torque (or at less that 1/2 the "torque range") as it's put in the article.

I am not a motor expert, but I strongly suspect that the efficiency depends on what type of motor you have. EG: I believe a stepper motor requires constant input power (regardless of how many steps it takes).

It would be nice if a real motor person fixed up this section. —Preceding unsigned comment added by (talk) 17:57, 5 March 2010 (UTC)

Most environmental electric engine[edit]

Appearantly, the Switched reluctance motor is the most environmental electric engine. Perhaps this info can be added to the article. (talk) 14:53, 29 May 2010 (UTC)


Engine strikes me as a rather quaint and old-fashioned way to refer to an electric motor. Any artifact with moving parts could be called an "engine" - we have after all the "difference engine". But I think its modern usage would be mostly for an internal combustion machine or a machine that works by the expansion of steam or other gases; a "heat engine", "Diesel engine", etc. Could we call an electric motor a "machine" that converts electrical energy to meechanical energy? --Wtshymanski (talk) 14:21, 21 October 2010 (UTC)

I'd much prefer machine to engine. Not for quaintness, but because "engine" is generally reserved for more complex items (rocket motor / rocket engine is illustrative). Despite also having quite an extensive library of early electrical engineering texts, I'd find it hard to cite examples of "electric engine" too. "Motor" is far more common, even from the earliest, and "machine" is pretty common too - although generally used for generators, rather than motors. Andy Dingley (talk) 14:31, 21 October 2010 (UTC)
I'm cool with "machine". I just felt like "An electric motor uses electrical energy to produce mechanical energy." was an injustice, because it was leaving out the machine/engine/motor part out. Wizard191 (talk) 15:30, 21 October 2010 (UTC)
Well, "injustice" might be hyperbole; I'd save that word for ratehr different circumstances. --Wtshymanski (talk) 16:05, 21 October 2010 (UTC)
Machine is too vague/general, so's a tin opener. I think we should really be linking to the parent type of machine, which is motor/engine.Planetscared (talk) 17:01, 21 October 2010 (UTC)
We're a bit limited by our linkage guidelines; ideally we would link 'An electric motor is a...', or we could go 'An electric motor is a motor...' but that's awkward. I mean an electric motor really is an electrical engine so far as I can tell, so the fact that it sounds quaint is largely just a nuisance.Planetscared (talk) 17:01, 21 October 2010 (UTC)
I don't think that the difference engine is actually an engine, you have to apply mechanical power to it, and it doesn't generate more mechanical power, so it's just a cute name.Planetscared (talk) 17:01, 21 October 2010 (UTC)
Hitting "Google Books", pretty clearly an "electric engine" is something that a railway would use to move rolling stock around, which is propelled by one or more "electric motors". And there's no point in redirecting the reader to "motor" which only has one relevant link, which is back to this article. If someone someday writes Brilliant Prose (a Wikimedia Foundation trademark that mysteriously is applied to the bland, prolix, ill-informed, inaccurate, and vauge pap that exists here on Wikpedia) that explores the topic "Motor" in all its glory, sure, link it...then. There's no deadline, in the mean time don't waste the reader's valuable life-span which he could instead be using to find naked pictures or to vandalize articles here. --Wtshymanski (talk)
We're not a dictionary. It's not at all about what it's called it's about what it is, based on the definitions of the thing.Planetscared (talk) 17:12, 4 November 2010 (UTC)
An engine is a thing that turns energy input into motion. That's also precisely what an electric motor is. Your argument that the phrase 'electric engine' usually refers to a railway engine is doubly irrelevant; not only did the article not call it that, but it's not how the article it linked to defined it either; and the machine article defines an engine as: "Engines" are machines that convert heat or other forms of energy into mechanical energy. Putting it as a 'machine' is so very, very vague, so's an axle.Planetscared (talk) 17:12, 4 November 2010 (UTC)
It's certainly not a heat engine, but it is an engine. Motor is simply synonymous with engine. Don't cars have motors pushing them along? Of course.Planetscared (talk) 17:12, 4 November 2010 (UTC)
Please provide some reliable citations that shows most people call that "thing with wires on one end that the electricity goes inot and a shaft on the other that mechanical power comes out" an "electric engine". We don't make up original definitions on the Wikipedia. --Wtshymanski (talk) 18:35, 4 November 2010 (UTC)
Another common type is the electric motor. This takes electrical energy and generates mechanical motion via varying electromagnetic fields. HalfShadow 18:37, 4 November 2010 (UTC)
Duh. Wikipedia is not a reliable source for Wikipedia. It doesn't serve the reader of "electric motor" to be diverted to "engine" in the 19th century physicist sense, when "electric engine" has a current specific meaning today of "a railway locomotive propelled by electric motors". --Wtshymanski (talk) 18:45, 4 November 2010 (UTC)
Hey, I couldn't care less; I'm just commenting in passing. HalfShadow 18:56, 4 November 2010 (UTC)
Are you seriously claiming that 'motor' is not synonymous with 'engine'? Are you also claiming that motors are not covered under the engine article? It seems to me that you're confusing heat engine with engine. They are not the same thing. Heat engine are subtypes of engine. A motor is something that creates motion. All engines are motors. I can point to any number of dictionaries that trivially support this.Planetscared (talk) 19:24, 4 November 2010 (UTC)
"Electric engine" is not synonymous with "electric motor" and referring to "engines" in the lead is in my opinion misdirecting the reader. Besides, my local copy of Merriam Webster says "Engine" is also synonymous with "machine". Why do we have three words for the same thing? Obviously because they aren't all the same. MW '76 also says an "engine" is something that converts heat, chemical energy, nuclear energy, radiation or the potential energy of suspended water to motion. So, one says an "air motor" or "hydraulic motor" but a "diesel engine". If you go to your local branch of GE, Toshiba, or WEG and ask to see their "electric engines" catalog, you'll be shown the door (well, maybe GE would give you a locomotive catalog). --Wtshymanski (talk) 20:45, 4 November 2010 (UTC)
A "steam engine" goes up and down - a "steam turbine" goes round and round. And a "steam motor" is usually a 19th century road vehicle propelled by a "steam engine". You can buy "hydraulic motors" today but if you go a'Googling for "hydraulic engine" you wind up with a bunch of 19th century books. An "air motor" goes round and round on compressed air, but an "air engine" is either a Stirling heat engine or else is again some 19th century invention. There's an 1878 book by Alexander Henry Green that refers to "electric engines" but is otherwise quite insane, as he proves that an electric engine cannot possibly work. --Wtshymanski (talk) 21:05, 4 November 2010 (UTC)
You're talking about phrases. The wikipedia isn't a phrasebook.Planetscared (talk) 01:10, 5 November 2010 (UTC)
Or, can you define what the difference between an engine and a motor is then? I frankly don't think you can.Planetscared (talk) 01:10, 5 November 2010 (UTC)
(And even if you can, it's beside the point. An electric motor is a motor, and motors are covered at Engine because there's at the very least huge overlap. So even if you can make a case for an electric motor not being an engine, we still need to link to that article.)Planetscared (talk) 01:10, 5 November 2010 (UTC)
But please, do give us a definition. Make sure it includes things like 'motor racing', 'motor car', 'motoring'.Planetscared (talk) 01:10, 5 November 2010 (UTC)
Lots of typing but beside the point. The machine that turns electric power into mechanical power is called a "motor" and that's what this article is about. An "electric engine" uses electric motors to propel cars down the track and is not the subject of this article. --Wtshymanski (talk) 13:19, 5 November 2010 (UTC)
Who the hell died and made you the decider of what is and isn't 'to the point'. The point is you are deliberately removing links to other articles that cover this topic, for reasons that amount to being a heap of crap. Nobody has even compared or linked this article to one on electric trains, but apparently, for you, you think you can claim that somebody has, and on that basis remove links to entirely different articles.Rememberway (talk) 21:23, 5 November 2010 (UTC)
I repeat. Why are motor cars, motor cars, and why can't I link an article on electric motors to one about motors?Rememberway (talk) 21:23, 5 November 2010 (UTC)
I will state this again, a motor is something that creates motion. All engines are motors, but (pretty dubiously IMO but arguably) not all motors are engines. We don't have a specific article on motors, we have one that covers motors.Rememberway (talk) 21:29, 5 November 2010 (UTC)
To be really pedantic: an "engine" is any tangible product of engineering. Thus all motors are indeed engines ragardless of their modus operandi. You could legitimately call your electronic pocket calculator a 'calculating engine' (and it was this usage that Charles Babbage employed when he named his difference engine and his analytical engine). In day to day usage, the word 'engine' is generally applied to a small subset of what it really encompasses.
-This contribution submitted via my Windows based computing engine!
Having just looked it up in a dictionary: it suggests an even wider definition:
Engine (noun)
a thing that is the agent or instrument of a particular process:
e.g. exports used to be the engine of growth
Hmm! Food for thought? (talk) 13:58, 11 February 2011 (UTC)

Rocket engines[edit]

And do the people building these things routinely call them "electric motors" ? I doubt it. Cite, please. --Wtshymanski (talk) 17:07, 18 November 2010 (UTC)

You continually seem to be unable to understand that articles are not about the title, they are about the scope of the topic, which is defined at the top of the article. The Wikipedia is not a dictionary, we're not trying to explain the usage of the term 'electric motor' at all, we're trying to cover what the article scope is. The article's encyclopedic scope is machines that turn electrical energy into mechanical motion. That's what these machines do.Rememberway (talk) 18:00, 18 November 2010 (UTC)
Oh. So you can't find anyone who calls a "rocket engine" an "electric motor". So why is it here? --Wtshymanski (talk) 19:04, 18 November 2010 (UTC)
Rocket Motors are never called engines by those who build them. During my employment at the Thiokol Chemical Corporation, Small Rocket Motors Division, of Elkton, Maryland I used the word "motor" hundreds of times a day. The usage is in thousands of NASA documents easily found with a search engine. A motor is a device that provides motive force, which is distinct from a gas generator such as an airbag inflator (which is chemically identical to a rocket motor). The only time rocket scientists use the word "engine" is when they are referring to their automobiles. :) — Preceding unsigned comment added by (talk) 17:44, 19 September 2012 (UTC)

Question re the Dyson-digital type of motor[edit]

I have no real background in electrical theory. My question here is a naive one, though it's one that may occur to others who may read this Wikipedia article after learning of news about the "Dyson digital motor."

The Dyson company has developed a battery powered "digital motor" that turns as high as 100,000 rpm. (See List of Dyson products, scroll down to DC12plus. From what I've read it is a very high-efficiency motor, as explained here:

Could a motor of this type be geared down so that — when providing, say 5000 rpm — the output torque of the motor/gear arrangement might then be useful for many applications other than a vacuum cleaner? while still outputting mechanical power at unusually high efficiency?

In other words, would an arrangement like this constitute a motor offering an ultra-high utilization of electrical power?Joel Russ (talk) 17:18, 2 January 2011 (UTC)

"Ultra high", no. It's efficient for its application, but gearing would lose a lot of energy at such speeds. Dicklyon (talk) 19:34, 2 January 2011 (UTC)
I have no information on the Dyson motor, other than the photographs on that site. Dyson have a habit of bizarre claims, some would say highly dubious claims of inventing particular mechanisms, so it's hard to believe a word that comes from their marketing. When it includes fatuous phrases like, "And no carbon brushes means no carbon emissions.", one is reminded why Dyson keep their poor reputation.
As to what the motor actually is, then it will be either a brushless motor or a stepper motor (both of which are quite similar). Neither of these are new, both are increasingly popular forms of motor for continuous rotation (steppers used to be thought of as positioning devices alone). Looking at the exploded view, it's a 4-pole stepper. They both trade modern electronics (cheaper and more reliable) in favour of brushes and commutators, with their friction, wear life and susceptibility to failure from inevitable wear. Dyson's real innovation is in their willingness to invest in production machinery, so they can afford to make a device with such tight tolerances, then sell it as part of a cheap domestic product. Narrow pole gaps (in any motor) mean efficiency, but they also demand better manufacturing.
As to "digital", then the motor is no more digital now than it has ever been. The control system will be digital, because that's just how cheap things are built these days. As to "pulses", then a stepper-like motor will be fed a train of pulses, a brushless motor will use something more like polyphase AC sine waves. Andy Dingley (talk) 19:36, 2 January 2011 (UTC)
Dicklyon, thanks. You wrote: "'Ultra high', no. It's efficient for its application, but gearing would lose a lot of energy at such speeds." Fair enough. The "Dyson digital" motor is judged to be simply efficient for its application. But, hoping I understand you correctly, if geared down to 3400rpm, 5000rpm, 1700rpm, something like that, it would not be "ultra-high" in efficiency for uses requiring more torque and less rpm.
Friction, inertial forces (that sort of thing) will reduce its efficiency, right? So is it the case that — geared down — its efficiency would be much like that of a brush-reliant conventional motor? Not only not "ultra-high" in efficiency, but actually not even "highly efficient"?Joel Russ (talk) 19:57, 2 January 2011 (UTC)
One of the first markets for stepper motors in continuous rotation applications was in slow-speed direct drives. They (unlike most motors) can drive efficiently at low speeds and can also have high torque, so they can avoid the gear train and its losses.
As to a geared down Dyson, then it will obviously lose some efficiency compared to its ungeared use. However its higher efficiency comes from two sources: the type of motor and also its high speed (this is always a good thing for inductive machines, provided that their drive electrics/electronics can keep up). Even if it loses the speed advantage, it still has the advantage of the different design. Andy Dingley (talk) 20:36, 2 January 2011 (UTC)
Andy, thanks. There is something I'm still missing here, and maybe it's due to my admitted lack of knowledge about electronics. But you wrote: "As to a geared down Dyson, then it will obviously lose some efficiency compared to its ungeared use. However its higher efficiency comes from two sources: the type of motor and also its high speed (this is always a good thing for inductive machines, provided that their drive electrics/electronics can keep up)."
Okay... Under load, any motor tends to lose speed, right? But gearing it down? That won't reduce motor-shaft speed all that much. Alright, say the gearing mechanism in itself (not under any further load) takes the motor-shaft speed and (due to drag) brings the motor output rpm down from 100,000 to 90,000; the motor itself is still spinning fast! Okay, so if the motor shaft were fed into a 20:1 gear set-up (IOW, "geared down"), with the rpm of the motor at 90,000, then the output speed of the gear mechanism would be about 4,500 — but, if I'm not mistaken, with the torque also stepped-up 20-fold.
Again, this is when not under load. The motor would be allowed to spin fast. Okay, the motor is still turning very fast, so how is the motor losing much efficiency?Joel Russ (talk) 01:42, 3 January 2011 (UTC)
Frictional losses for an efficient high-speed motor with a gearbox will swamp its benefits, compared to an inherently less efficient design of motor that is however slower, so that it doesn't require the gearbox. It's rare that adding a gearbox to a design is ever worthwhile (on efficiency grounds) - only if it would then permit the use of a significantly more efficient prime mover. The only example I can think of off-hand is that of steam turbines appearing in ships around 1910. These were used in fast naval destroyers before this date, without gearboxes, and their higher performance & cost could be justified for specialised naval use. However they didn't move into fast passenger liners until gearboxes were available to match the turbine and propeller speeds.
For motors, a 20:1 high-speed gearbox would be losing enough power that I'd be really surprised if it was still competitive with a simpler brushed motor that already ran at the slower speed. However I don't think this is the case anyway - why not just redesign the new brushless motor to run at a design speed of 4,500rpm directly? Although probably not as effcient as the 100,000rpm motor, it could well still have enough advantage over the brushed motor (the advantage it gained from the new brushless design, not any other advantage it might gain from the higher speed). Andy Dingley (talk) 02:57, 3 January 2011 (UTC)

Stepper motor, or not?[edit]

In the article, there is the statement:

Stepper motors were and still are often used in computer printers, optical scanners, and digital photocopiers to move the optical scanning element, the print head carriage (of dot matrix and inkjet printers), and the platen. Likewise, many computer plotters (which since the early 1990s have been replaced with large-format inkjet and laser printers) used rotary stepper motors for pen and platen movement; the typical alternatives here were either linear stepper motors or servomotors with complex closed-loop control systems.

that I don't completely agree with. While steppers are used in the slower cases of scanners and printers, as far as I know, more often an open loop servo system is used. For scanners, an optical position sensor (LED/phototransistor pair and a strip of black and transparent stripes) allows the controller to know the position of the scan/print head independent of the motor speed. The Ricoh scanner that I have will slow down the scan as the buffer fills and speed up as it empties, and yet the scan comes out just fine. The open loop system allows for a cheaper motor and still accurate positioning. Gah4 (talk) 12:37, 26 January 2011 (UTC)

So what's your point? It's a big world. For any possible way of doing something, someone, somewhere will have tried it. Yet the majority are still cheap open-loop with a stepper, and a zero position sensor at most. Nor does this rule out running at a variable speed. The quote doesn't claim that everything is this way and no other, just that it's the common way of doing it. Although I've seen closed loop systems with incremental encoders (pulses, not a position signal) in the past, I don't recall seeing one for years now. Steppers are cheap, and compared to a gearhead motor with comparable torque, they're very cheap.
I'm also unclear what you mean by an "open loop servo system"? Andy Dingley (talk) 12:47, 26 January 2011 (UTC)


Made 2 images, first image showing the arrangement of the magnets in brushless, and brushed electric engines. Second image shows commutator/brushes setup for 1, two and three phase engines. First image needs update (adding of AC-variants), and second one might need one too (to include brushless engines; if indeed the setup is different for them).

File:Main types electric engines.JPG
Main types of electric engines
File:1 2 3 phase E engine.JPG
1, 2 and 3-phase electric engine (talk) 10:09, 29 January 2011 (UTC)

Hello KVDP. In a word, No. Andy Dingley (talk) 10:36, 29 January 2011 (UTC)
Sure glad that issue's cleared out. Anyway here's another image. Perhaps you like this one better ?
File:Brushed electric engine.PNG
Workings of brushed electric engine (talk) 15:00, 3 February 2011 (UTC)

None of these are suitable. --Wtshymanski (talk) 15:50, 3 February 2011 (UTC)
Once again, you have created a rubbish image and planted it into articles. There are the same problems with this as ever:
  • It's rubbish. You can't even copy another image from the web without "improving" it and making it misleadingly incorrect and just plain wrong.
  • You have no idea what you're describing (very obviously so). You seem to think that it's possible to write about this stuff without first making some effort to learn what you're talking about.
  • You refuse to listen to any comment when you make exactly the same mistakes, for the same reasons. Five images in a week, all garbage? Don't you think there's a moral somewhere in this story?
Please stop. We have better things to do. Andy Dingley (talk) 23:39, 4 February 2011 (UTC)

The principle[edit]

The principle of alternating the magnetic field, and how the magnetic field is generated in missing from the "The principle" which does not talk about the principle at all, but merely the history. Is that intentional? Adacus12 (talk) 01:37, 6 March 2011 (UTC)

The principle is that the supplied electric current produces a magnetic field that causes the rotor to keep rotating continuously, one small angle at a time. (talk) 04:46, 4 August 2016 (UTC)

How fast can we get these motors to go?[edit]

I am designing an airplane that only runs off of solar power energy and I need to get the electric motor to spin at 30,000 RPM. The problem I am thinking that it's impossible to reach 30,000 RPMs. Also I was wondering if we could place a turbo charger on the motor to increase the speed.

TheGoToGuy1 (talk) 16:17, 7 March 2011 (UTC)

This is not the Help Desk. This page is for discussion of improvements to this article. --Wtshymanski (talk) 16:34, 7 March 2011 (UTC)

Amperage and current in electric motors[edit]

Fundamental to the operation of electric motors is the flow of current (AC/DC). The article needs to characterize the electrical measurement of amperage as a primary attribute of motor performance. — Preceding unsigned comment added by (talk) 15:11, 19 July 2011 (UTC)


"Telechron™ clock motors" .. specific brands shouldn't be named explicitly. Makes the article less encyclopedic. — Preceding unsigned comment added by (talk) 23:01, 30 July 2011 (UTC)

The telechron is a critically important subject to anyone studying the creation of the power grid or the history of frequency alignment in grid-connected power sources. Just as passing references to Henry Ford and Gottfried Daimler are appropriate to articles about mass production of automobiles, a reference to the groundbreakingly significant telechron's frequency locked AC motor is appropriate here.
Note also telechron is no longer a business, so it can hardly be an advertisment to mention it.

File:Jedlik motor.jpg Nominated for Deletion[edit]

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In efficiency section, how about introductory prose that summarizes the key concepts in words[edit]

Right at the start, a summary of the efficiency of conversion of electricity into torque with various types of motors would help those less able to read equations, and would set the mental table for those comfortable with equations.

Perhaps summarize the ranges of efficiency of various types of motor in a table? — Preceding unsigned comment added by Ocdnctx (talkcontribs) 17:38, 20 November 2011 (UTC)

"Probable future directions" - possible to add such a predictive section?[edit]

Would it be possible to add a section in the article that discusses experimental innovations? A section that reports a bit on knowledgeable speculations as to where electric motor development is likely to go?

I like the article. However, I'd be interested to learn, for instance, what the thinking now is about increasing efficiency: by what means could a given wattage of input conceivably result in a greater output of usable mechanical power?Joel Russ (talk) 01:05, 9 December 2011 (UTC)

Sounds a bit crystal-ballish to me. I would confine it to specific well-documented projects already in progress. You might find something on superconducting motors and why they still haven't taken the world by storm, for instance. Some knowledgeable and referenced commentary on conversion to energy-efficient AC induction motors would be appropriate. But I wouldn't get too carried away trying to predict the efficiency of electric motors in 2100, let alone 2030. There may not be a lot of low-hanging fruit left to gather in that orchard anyway, since AC motors of typical industrial sizes already reach in the low 90's for percentage efficiency at full load. --Wtshymanski (talk) 14:55, 9 December 2011 (UTC)
I did not have any particular inventions or theories in mind, personally. I mentioned the above because I, for one, would like to be able to learn a little something about current plausible theoretical directions, and current experiments. Perhaps others would be similarly interested. I believe such additional material would not be "crystal-ballish" - if the contributions were made by the right person(s).
However I agree with your overall concern for prudence. Indeed, no need to "get too carried away" as you put it.Joel Russ (talk) 22:46, 9 December 2011 (UTC)
Find reliable sources discussing research efforts and accomplishments aimed at more output HP for fewer watts or volt-amps in. You may find that efforts to achieve this have been going on steadily for the last 130 years or longer. "High efficiency" motors came along ion the 1980's, if memory serves, because I recall problems with new installations of them causing CB trips from the motor inrush current, when the breakers were "correctly" sized for the motors.New motor start and run curves had to be allowed for. See [1] and [2]: "This allows the instantaneous pickup to be adjusted to a value slightly above motor inrush so that low level faults ... in applying high-efficiency motors are (1) replacing a standard motor with a high-efficiency motor and (2) the need .." per the snippet.But then back in 1911 they also compared standard and "high efficiency" motors:[3]. Edison (talk) 22:58, 9 December 2011 (UTC)


The section on Operating principles should be split out to Operating principles of electric motors or some sort of similar title. It is too big for the article giving it the wrong balance. -- Alan Liefting (talk - contribs) 21:59, 12 March 2012 (UTC)

Yeah... It is too big. Will take a look at it later. Roshan220195 (talk) 05:11, 15 April 2012 (UTC)
The quality scores are about the highest I've ever seen. If you split it, you'll just end up with two mediocre articles. Splitting isn't a good idea at all, but it is a bit flabby, needs tightening up in places, but not splitting.Teapeat (talk) 13:27, 15 April 2012 (UTC)

Motot constant[edit]

Found this at

== K<sub>M</sub> rating == ''K<sub>M</sub>'' is the ''motor constant'' (sometimes, ''motor size constant''), defined as: :<math>\frac{\tau}{\sqrt{P}}</math> where * <math>\scriptstyle \tau</math> is the motor torque (SI units, N·m) * <math>\scriptstyle P</math> is the resistive power loss (SI units, W) The motor constant is winding independent (as long as the same conductive material used for wires); e.g., winding a motor with 6 turns with 2 parallel wires instead of 12 turns single wire will double the velocity constant, K<sub>v</sub>, but K<sub>M</sub> remains unchanged. K<sub>M</sub> can be used for selecting the size of a motor to use in an application. K<sub>v</sub> can be used for selecting the winding to use in the motor. /

also this == K<sub>v</sub> rating == <!-- [[Kv]] links here. If you change this heading, please fix the link at [[Kv]].<ref>[ United Hobbies: "Kv rating explained"]</ref> --> ''K<sub>v</sub>'' is the motor velocity constant, measured in RPM per volt (not to be confused with ''kV'', the abbreviation for ''kilovolt'')<ref>[ United Hobbies: "Kv rating explained"]</ref>. The K<sub>v</sub> rating of a brushless motor is the ratio of the motor's unloaded RPM to the peak (not RMS) voltage on the wires connected to the coils (the ''back-EMF''). For example, a motor of K<sub>v</sub>, 5,700 RPM/V, supplied with 11.1 V, will run at a nominal 63,270 RPM (5,700 RPM/V × 11.1 V). By [[Lenz's law]], a running motor will create a back-EMF proportional to the RPM. Once a motor is spinning so fast that the back-EMF is equal to the battery voltage (also called DC line voltage), it is impossible for the motor to be driven faster. /

It looks to me as if the scope is well beyond the original article and if put anywhere - it should be here. The second part refers to brushless motors but is universally applicable.Oranjblud (talk) 21:54, 22 March 2012 (UTC)

It's pretty much vital to coverage of brushless motors. It shouldn't be removed. Andy Dingley (talk) 22:01, 22 March 2012 (UTC)
I've created Motor constants using the info and linked to it. I'll check the links for Kv and Km. I'll leave it to others to check for other relavent links..Oranjblud (talk) 22:27, 22 March 2012 (UTC)

Electric motor history tabulation[edit]

Here is tentative rough draft called 'Electric motor history tabulation' for consideration in inclusion somehow in Electric motor

Date, Name Electric Motor Chronology Selected Patents
1820, Oersted Danish, physicist and chemist; first to note a compass needle deflected from magnetic north when an electric current from a battery was switched on and off, confirming a direct relationship between electricity and magnetism.[1][2][3][4]
1820, Ampère French, physicist; invented the solenoid.[1][4]
1822, Barlow British, physicist; invented Barlow's wheel, the first device ever powered by electromagnetism.[1][3][5][4]
1824, Arago French, physicist; showed a rotating copper disk produced rotation in a magnetic needle suspended above it, which Faraday later attributed to induction phenomena.[6][4][7]
1828, Jedlik Hungarian, physicist and unsung father of the dynamo and electric motor; invented the first commutated rotary electromechanical machine with electromagnets.[1][3]
1831, Henry American, physicist; formulated, independently from Faraday, induction law and created a mechanical rocker, which he however describes as a philosophical toy.[1][8][4]
1821  &  1831 Faraday British, scientist; 1821 - showed continuous 'electromagnetic rotation' resulted by suspending a magnetic wire in an electric field;[1][2][3][4] 1831 - discovered and investigated induction law in terms of electric current generation in a varying magnetic field.[1][3][8][4]
1825-1833 Sturgeon British, scientist; 1825 - invented the electro-magnet; 1833 - built first commutated rotating electric machine that was demonstrated in London.[1]
1832-33, Pixii French, instrument maker, built the first AC generating apparatus out of a rotation; and, the following year, an oscillating DC generator.[1][3][4]
1833, Saxton American, inventor; demonstrated an magneto-electric machine before the British Association for the Advancement of Science.[8]
1833, Lenz German; formulated the law of reversibility of generators and motors.[2][1][4]
1837, Davenport American, blacksmith-inventor; obtained first US electric motor patent.[1][3][5][8] US 132
1838, Solomon Stimpson American; built a 12-pole electric motor with segmental commutator.[9][5][8] US 910
1834-39, Jacobi Russian, engineer and physicist; built a 15 watt motor in 1834 submitted to the Academy of Sciences in Paris with detailes published in 1835; demonstrated first use of electric motor to propel a boat; first real useful rotary electrical motor.[9][1][3][8][4]
1840, Truman Cook American; built electric motor with a permanent magnet armature.[9][8] US 1735
1837-42, Davidson Scottish, inventor; developed electric motors for a lathe and a locomotive.[9][1][3][8][8]
1845, Froment French, engineer and instument maker; first of various motors, translates linear "electromagnetic piston's" energy to wheel's rotary motion. See also Mouse mill motor.[9][10][8][8][4]
1856, Siemens German, industrialist; invents generator with a double-T armature and slots windings.[1][4]
1861-64, Maxwell British, scientist; reduces electromagnetism knowledge in four key equations.[1][3][4]
1871-73, Gramme Belgium, engineer; developed the anchor ring motor which solved the double-T armature pulsating DC problem; at Vienna exhibition, demonstrated to great effect ability to transmit between generator and motor 1 km apart.[1][4]
1879, Walter Baily British; by manual switching on and off, developed the first primitive commutatorless induction motor.[2][7]
1885, Ferraris Italian, physicist and engineer; invented the first alternating current commutatorless induction motor using two-phase AC windings in space quadrature.[11][1][2][7]
1886, Sprague American, industrialist; development of new constant-speed DC motor, which allowed the Sprague company to issue the world's "first important industrial electric motor catalogue".
1885-89, Tesla Serbian-American, engineer and physicist; having worked independently from Ferraris, presented a key paper in 1888 to AIEE describing three patented two-phase four-stator-pole motor types: one with a four-pole rotor forming a non-self-starting reluctance motor, another with a wound rotor forming a self-starting induction motor, and the third a true synchronous motor with separately-excited DC supply to rotor winding. This led to Westinghouse acquiring exclusive rights to him patents and retain him as a consultant to work on development of these motors.[1][2][3][7][4] US 0,381,968
US 0,381,969
US 0,382,279
US 0,382,280
1889-90, Dolivo-Dobrovolsky Russian, engineer and inventor; invented the first cage and wound rotor versions of the three-phase induction motor that are still widely in use today.[1][2][3][7][4]

All comments much appreciated of course.Cblambert (talk) 08:16, 16 February 2013 (UTC)

  • Comment: Small points - Reference and consensus has Tesla as "Surbian-American", Westinghouse leased the patents, he did not buy them. Also "This led to Westinghouse buying his patents and hiring him to work on development of these motors" - supplied reference does not support this wording. According to this reference Westinghouse already had all the components in some form, or had access to them (via Ferraris). He was "led to... buy" because it was a potential priority patent undermining a system he was already building. Also Westinghouse may have known about Tesla's motor before the AIEE demo. Fountains of Bryn Mawr (talk) 18:31, 16 February 2013 (UTC)
Agreed Tesla is indeed Serbian-American.
The evidence is overwelming that Westinghouse 'bought' the patents. Technically it may have been 'exclusive rights' or words to that effect, which amounts to buying. It is also well know that Westinghouse paid an exhorbitant amount for the patents. So much indeed, that when Westinghouse got in finanicial trouble Tesla tore off the contract, which allow Westinghouse to avoid bankruptcy. Westinghouse may indeed have bought that Ferraris patents for $1,000. Who would not do the same for so little money. . . .Cblambert (talk) 20:24, 16 February 2013 (UTC)
Its all allot to boil down..... Westinghouse did not buy the patents until 1897, and Tesla did not tear up the contract - it was a patent buy out for a lump payment (claimed at $216,000). Also Tesla was a one third partner with Peck and Brown so its doubtful he could "tear up" anything on his own. Also there were many reasons for the buyout, with JP Morgan in the background taking over Edison, backing Westinghouse, and arranging an eventual patent pool....... In other words, we should probably avoid standard "Tesla lore" in a limited paragraph/table. Fountains of Bryn Mawr (talk) 17:42, 17 February 2013 (UTC)
If it's good enough for IEEE Global History Network's Tesla biography,
"After agreeing to a contract that turned over AC development and patents to the Westinghouse Corporation, Tesla became a wealthy man. When Westinghouse got into financial difficulties later, Tesla supposedly tore up his contract and refused further royalties for his patents."
and for Arnold 'Mr. Induction Motor' Alger's "History of Induction Motors in America" in Proceedings of IEEE,
"George Westinghouse at once [after the AIEE paper presentation] bought Tesla's patents and employed Tesla to develop them."
and for Doppelbauer,
"George Westinghouse becomes aware of Tesla in May 1888 due to his remarkable speech in Pittsburgh to the American Institute of Electrical Engineers, and buys his more than 40 patents for $ 1 million. In addition, he hires Tesla as a consultant for his company."
it's good enough for me. Note that IEEE GHN biography says Tesla was born in Crotia from Serbian parents. I concede that Westinghouse hired Telsa as a consultant. I would appreciate it if you did not patronize me, please.Cblambert (talk) 20:42, 17 February 2013 (UTC)
Sorry, but it isn't good enough for Wikipedia, that is why we have WP:V. The ins and outs of Tesla's deals via Brown and Peck are well documented[4][5]. Tangential sources you quoted boil this stuff down or re-quote other sources and give unverified numbers such as "$1 million", but give no basis for it. BTW If you are going to ask for a review you should not take it personally. Fountains of Bryn Mawr (talk) 21:28, 17 February 2013 (UTC)
I appreciate the comments but this is an article amount electric motors in which you want to summarize what happened historically, which is the intend of the section as set out at the outset above. IEEE GHN, Alger and Doppelbauer are as authoritative as they come. From what I can see your sources are if anything only marginally more authorative than the ones offered and certainly not worth arquing about here. You may want to quibble about a word here and there but that is not the intent. Further comments are welcome to the extent that the discussion is constructive and quickly leads to closure. Please propose specific concrete alternatives to the intent.Cblambert (talk) 21:53, 17 February 2013 (UTC)
Changes made to Tesla entry of above tabulation in terms of suggestion about Serbian origin as well as Westinghouse retain Telsa as consultant and acquiring exclusive rights to Telsa's patents.Cblambert (talk) 00:11, 18 February 2013 (UTC)

On history with list of actual realisations, see also Meeùs (talk) 20:10, 1 July 2014 (UTC)

  • The evidence that Jedlik made a significant contribution to the early development of electric motors is extremely weak and appears to be based on nationalistic claims.I have read many 19th century accounts of the development of electric motprs and generators and nowhere have I found anything to back up the claims introduced here. He did some generator work much later. I fear popuar writers will blindly copy what this article says about Jedlik and it will become enshrined as fact without any good sourcing. He certainly was a science teacher and some models of electrical machines were found in the inventory of his school decades after his supposed invention of them, but it could just as well be the case that he read about things others developed, then built classroo demonstration versions of them, then other in the 20th century made wild claims for his priority. Others wrote up their inventions and gve public demonstrations in the 1830's and 1840's, but Jedlik was supposedly content to show them to his students, then put them away in a storeroom. Edison (talk) 20:05, 3 November 2014 (UTC)

Major reservations about ‘Major categories’ section[edit]

Referring to Major categories and, at the end here, electric motor template, it would be important to get consensus between the two different 'characterizations', my sense being that with the template finalized one hardly needs detailed Major categories except as a recap perhaps. But by far the biggest issue is that I have major reservations about tabulation in Major categories in terms of the following:

  • Tabulation misses the point in that, to quote from Tesla's famous 1888 AIEE paper, “. . . all machines are, in fact, machines with alternate current and the currents appear as direct current machines only in the external current circuit during their passage from the dynamo into the motor.” (See Vučković, p. 178) Who cares if drive input is DC? What matter is what the motor input is.
  • It may be confusing and a bit counterintuitive but it remains BLAC does not exist! BLAC should there not be in tabulation, in WP BLAC article or anywhere else in the world.
  • Idea of BLDC actual being derived from AC source is that it replaces DC motor but with quasi-DC-motor performance and the input of the motor is with ‘ trapezoidal’ AC waveform whereas the ideal for drives is for more to have ‘sinusoidal’ AC waveform; ie, the stator winding is distributed evenly instead of being distributed with sinusoidal interval.
  • Tabulation also misses the point about induction motor rotor being copper. The induction motor is real identical electromagnetically to a transformer that happens to have an air gap. So the tabulation should, if anything, refer to the rotor winding being perhaps copper but more often of molded aluminum construction.
  • Tabulation does not identify wound-rotor induction motor.
  • Tabulation mixes up motors in all matrix cells except one cell showing inverter. Confusing.
  • I am still investigating is the VRM category should be AC or both AC and DC, but and Bose 2006 reference above show AC.
  • Tabulation does not cover all the bases.
  • And so on and so forth.

The tabulation does more harm than good. Tabulation should be scrapped.Cblambert (talk) 22:52, 16 February 2013 (UTC)

I decide to revised tabulation.
In case there are any doubts about BDLC, I show excerpt from TI as follows:
"This motor is referred to as a "DC" motor because its coils are driven by a DC power source which is applied to the various stator coils in a predetermined sequential pattern. This process is known as commutation. However, "BLDC" is really a misnomer, since the motor is effectively an AC motor. The current in each coil alternates from positive to negative during each electrical cycle. The stator is typically a salient pole structure which is designed to produce a trapezoidal back-EMF waveshape which matches the applied commutated voltage waveform as closely as possible. However, this is very hard to do in practice, and the resulting back-EMF waveform often looks more sinusoidal than trapezoidal. For this reason, many of the control techniques used with a PMSM motor (such as Field Oriented Control) can equally be applied to a BLDC motor."
Refer to Overview - Motor Drive & Control Brushless DC Motors (BLDC) - Not a word about BLAC.Cblambert (talk) 06:17, 20 February 2013 (UTC)

Major ==History== section quality issues[edit]

As recently done with ==Performance parameters== section, ==History== section should probably be demoted to the end of Electric motor article, is only temporarily. My view is that treatment in the ==History== section is of generally poor quality. Reasons for this include:

  • Fact that section overly emphasizes dumbed-down physics education aspects (St. Louis motor, brine experiments, and simplistic notions re efficiency, progress delay for a century due to air gap, heroic assumption linking efficiency progress to St. Louis motor, and so on and so forth.
  • Treatment is clearly lopsidedly biased toward's Jedlik and Spraque.
  • There is a ludicrous number of citations in the ==Emergence of AC motors== section.
  • As is now, Electric motor is two articles fighting for supremacy: An 'Electric motor history' article and a 'Electric motor types' article.
  • One good benchmark to compare with is Transformer article.

Indeed, the contrast between Transformer and Electric motor cannot be more stark, the good old step-by-step scientific method evident in the former having been instead hijacked by the high school Physics class in the latter: after a deeply flawed overdrawn history, but no technical preamble, just jump in the ==Major categories== deep water right away!! I invited discussion prior to taking further editing act.Cblambert (talk) 23:53, 25 February 2013 (UTC)

P.S.: It could well be that separate 'Electric machine history' is in order. Here is who J. F. Mora shows, from his comprehensive overall list of famous historical electrical engineering figures, for the 'Electrical Machine' field (which includes transformers)[12] :

Adams, Comfort Avery - Alexanderson, E. F. W. - Alger, Philip Langdon - Arnold, Engelbert Barlow, Peter - Behn-Eschenburg, Hans - Behrend, Bernard A. - Berresford, Arthur W. - Blathy, Ottó Titusz - Blondel, André - Boucherot, Paul - Boveri, Walter - Brown, Charles E. L. - Buchholz, Max - Clarke, Edith - Concordia, Charles - Crompton, Rookes E. B. - Danielson, Ernst - Darrieus, George - Davenport, Thomas - Déri, Miksa - Doherty, Robert E. - Dolivo-Dobrowolsky, M. - Edison, Thomas Alva - Eichberg, Friedrich - Faraday, Michael - Farmer, Moses Gerrish - Ferguson, Louis A. - Ferranti, Sebastian Z. de - Ferraris, Galileo - Fitzgerald, Arthur Eugene - Fleming, Sir John A. - Fontaine, Hippolyte - Forbes, George - Fortescue, Charles - Gaulard, Lucien - Gerard, Eric - Giorgi, Giovanni - González Echarte, Antonio - Gorges, Johannes - Gramme, Zenobe T. - Hadfield, Sir Robert A. - Halske, Johann Georg - Haselwander, Friedrich - Hefner-Alteneck, Friedrich - Heyland, Alexander - Highfield, John Somerville - Hjorth, Sören - Hobart, Henry Metcalf - Hopkinson, Edward - Hopkinson, John - Jackson, Dugald C. - Janet, Paul - Kandó, Kálmán - Kapp, Gisbert - Karapetoff, Vladimir N. - Keith, Nathaniel - Kimbark, Edward W. - Kingsley, Charles - Kittler, Erasmus - Kloss, Max - Krämer, Christian - Kron, Gabriel - Kurda, Karl - La Cour, Jens Lassen - Laithwaite, Eric - Lamme, Benjamín - Leblanc, Maurice - Leonard, H. Ward - Mac.Cutcheon, A. - Madariaga Casado, J. M. - McAllister, Adams S. - Miller, Oskar von - Moeller, Franz - Mordey, William Morris - Morillo Farfán, José - Ollendorf, Franz H. - Ossanna, Johann - Pacinotti, Antonio - Park, Robert H. - Perez del Pulgar, J. A. - Pixii, Hippolyte - Potier, Alfred - Punga, Erwin - Rathenau, Emil - Richter, Rudolf - Rojas y Caballero, F. - Rosenberg, Emanuel - Rüdenberg, Reinhold - Saxton, Joseph - Scherbius, Arthur - Schrage, Hidde Klaas - Schuckert, Sigmund - Scott, Charles Feldon - Siemens, Werner von - Siemens, Sir William - Sprague, Frank Julian - Stanley, William - Steinmetz, Charles P. - Stillwell, Lewis - Terradas Illa, Esteban - Tesla, Nikola - Thompson, Silvanus P. - Thomson, Elihu - Veinott, Cyril George - Wagner, Charles F. - Wenström, Jonas - Westinghouse, George - Wheeler, Schuyler S. - Wiedeman, Eugen - Wilde, Henry - Wilson, Ernest - Wimshurst, James - Zipernowsky, Károly - Cblambert (talk) 23:53, 25 February 2013 (UTC)

PSS: That's about 115 names for Electric Machine (EM) field. As I recall, Mora lists about 500 names overall for all EEs fields including computer etc.; ie, 1/4 of the names for EM field. Which seems to be balanced enough distribution of names.Cblambert (talk) 16:51, 7 March 2013 (UTC)

View stats mapping of Electric motor template[edit]

Food for thought in connection with 'Electric motor' template view statiscis mapping for the 90-day period ended last March 8, 2013.

View stats for 90-d. period ending on Thur. 7Mar2013 Ranked in descending views order by 'Electric motor' template's categories 0 to 13
View stats  % views  % cum
WP rank
9-Motor controllers 510,757 20.3 20
0-Electric motor article 379,902 15.1 35 4.713
13-Abbr. (Magnet) 286,869 11.4 47 7,066
12-See also 263,251 10.5 57
7-Special magnetic motors 248,055 9.9 67
5-AC asynchronous machine 237,879 9.5 77
1-Root AC & DC motors 229,358 9.1 86
4-AC electronic-commutator motor 131,426 5.2 91
6-AC synchronous machine 96,050 3.8 95
2-DC machine 74,870 3.0 98
8-Non-magnetic 30,089 1.2 99
10-Motor history, ed., rec. 15,312 0.6 100
3-AC mechanical-commutator motor 8,940 0.4 100
11-Emerging (Superconducting) 3,400 0.1 100
Total 2,516,158 100 100
View stats for 90-d. period ending on Thur. 7Mar2013 Top 31 article ranking (> 10,000 views, 96% of overall) Of 'Electric motor' template categories
View stats  % View stats  %
0-Electric motor 379,902 7-Linear motor 29,074
13-Magnet 286,869 2-Homopolar motor 28,948
9-Power inverter 203,999 7-Traction motor 21,631
5-Induction 202,975 9-Vector control 18,959
12-Alternator 177,381 12-Brush 18,360
7-Stepper 156,819 6-Synchronous reluctance (SyRM) 15,693
9-VFD 144,574 4-Switched reluctance motor (SRM) 15,639
1-DC machine 128,137 8-Ultrasonic 15,629
4-BLDC motor 115,787 5-Shaded-pole motor 12,769
1-AC machine 101,221 12-Rotor 12,716
6-Synchronous 73,036 5-Linear induction 11,841
9-Motor controller 58,059 9-Cycloconverter 11,032
2-Brushed DC motor 43,999 9-AC/AC converter 10,553
12-Stator 41,466 5-Wound-rotor induction motor (WRIM) 10,294
9-Soft starter 32,381 9--Direct torque control (DTC) 10,094
7-Servomotor 30,831
Total 2,177,436 86.5 2,420,668 96.2

The remaining 22 articles figuring in Electric motor template, with, in descending order of importance, less than 4% of 90-d. views, are as follows:

7-Doubly fed electric machine, 8-Piezoelectric motor, 6-BLAC, 9-Ward Leonard control, 9-Voltage controller, 10-Ball bearing motor, 3-Repulsion motor, 8-Electrostatic motor, 12-Braking chopper, 9-Amplidyne, 12-DC injection braking, 3-Universal motor, 11-Superconducting electric machine, 10-Mendocino motor, 12-Booster, 10-Barlow's wheel, 9-Thyristor drive, 10-Lynch motor 12-Inchworm motor, 2-Unipolar motor, 9-Metadyne, and 10-Mouse mill motor.

This will hopefully help place in perspective opportunities for merging articles will too much overlap as for example:

P.S.: I find Magnet interesting in light of WP ranking and long-term potential for electric motor efficiency improvment with permanent magnet based BLDC and BLAC/PMSM.Cblambert (talk) 23:46, 9 March 2013 (UTC)

There doesn't seem to be any overlap at all between repulsion motors and universal motors.Teapeat (talk) 01:02, 10 March 2013 (UTC::
I agree there is no overlap per se for that bullet. I prefaced suggestion point in too-broad brush strokes. In the case of these two articles, I am thinking that there view stats are so small as to be irrelevant unless grouped together as more all-inclusive article. I have no strong feelings about that particular bullet. I am rather looking for cues to interprete this data.
Re revelance clarification, thyristor drive being very close the bottom end of the irrevalency sprectrum, bullet about VFD should in fact read:
The stats are in fact not very small for universal motor, it has only existed for about a week, and while it is not very, very popular, it is getting a similar number of hits per day as many of the other articles in your main list. As to your suggestion that it be renamed, in Wikipedia articles are virtually always named by the most common name, rather than the very most technically accurate name, per Wikipedia:Article titles. Article titles are a way for the users to find the article, rather than being an exercise in total precision.Teapeat (talk) 04:18, 10 March 2013 (UTC)
I see that you Universal has been only recently created. My suggestion is more rhetorial than prescriptive. I'm trying to come to grips with what is good way of grouping overarching topics like Transformer and Electric motor. Former has evolved so main Transformer articles treats only overview aspects leaving it to other articles to handle transformer types as combination of Transformer types and specific special transformer articles. And indeed, for example, decent Distribution transformer (arguably proportionally much more important than Universal motor article has only `10,000 90-d. stat. But, Transformer now consciously excludes treatment of types, including that of distribution transformer, from the main article. So maybe the question is why not (for example) does Electric motor main article duplicate unversal motor in both Electric motor section and in it's own main article. Why does Electric motor main article not have Repulsion motor but has its own main article, even though Repulsion motor's own main article has more views than Universal motor's own main article? In other words, why these fundamental differences in approach to Transformer and Electric motor? What all this overlap between Electric motor and specific motor main articles? Is there a guide for handling this? Does anybody else have ideas about this?Cblambert (talk) 05:21, 10 March 2013 (UTC)
I'm more questioning whether the electric motor article is covering the main points about electric motors. While it enumerates the many different types well, how would you calculate the torque of an arbitrary electric motor for example? Presumably the Lorentz force law for wires applies. Also magnetic pressure is also quite related I think. And yet these things are not found anywhere. What is the relationship between efficiency and field strength and rpm. What is field weakening?Teapeat (talk) 01:42, 11 March 2013 (UTC)
I think there's a lot of things that apply to virtually all, or indeed applies to all motors that isn't being covered well right now.Teapeat (talk) 01:42, 11 March 2013 (UTC)
Sorry. I did not see these 2 comments. Rome was not built in a day. The fundamental magnetic principles do indeed need to be fleshed out. The usual approach to motor principles quickly gets one involved in electric engineering techniques which can fast overwhelm the lay reader. One the easiest way to visualize what is happening in induction motors is the circle diagram and associated Blocked rotor test and open circuit test. The other more intense techniques leads to mastering an understanding of motor's Steinmetz equivalent circuit principles. The induction motor equivalent circuit is treated very very similar that of a transformer. A third approach leads to mastering of vector control (motor), which is not easy, but is intriquing because at the holy grail of AC induction and synchronous is to get to the point where AC motor is treated like a DC motor with a seperately-supplied field such that torque and flux control 'decoupled' . With powerful DSPs this is now relatively easy to achieve. Many, many technical people have been working on this holy grail for the past 3 decades. Reaching consensus on willingness to tackle and to eventually do justice to these issues is the most important first step. The rest may not be easy but is doable. That's my view.
Also, the template's 3-AC mechanical-commutator motor category, which combines both Repulsion and Universl, has 8,940 views or only 0.4% for the category, 0.2% average. Universal might double views in long-term. But this is pretty small number of views. Same sort of views, ~0.2% views average. as for the 22 articles totally <3.8%. I would not say this is something to be in awe with. Maybe nothing wrong with this, but nothing to write home about.Cblambert (talk) 05:57, 10 March 2013 (UTC)

Filling out the 90-d. view stats picture in historical terms, from Tesla way on top with am amazing million views, to Froment's insignificant 329 views, and Jedlik and Sprague hanging on with around 5,000 views each.Cblambert (talk) 18:52, 10 March 2013 (UTC)

View stats for 90-d. period ending on Sat. 9Mar2013 Ranked in descending view order of twenty-four Engineers and scientists
Views WP rank Views
Nikola Tesla 1,052,416 986 Frank J. Sprague 4,863
Michael Faraday 229,467 Thomas Davenport 4,266
James Clerk Maxwell 133,749 Galileo Ferraris 3,973
André-Marie Ampère 36,708 Hippolyte Pixii 2,964
Hans Christian Ørsted 36,530 Mikhail Dolivo-Dobrovolsky 2,824
Joseph Henry 20,583 Zénobe Gramme 2,659
Charles Proteus Steinmetz 14,958 Peter Barlow 1,826
Werner von Siemens 11,933 Moritz von Jacobi 1,686
François Arago 9,296 Robert Davidson 1,519
William Sturgeon 6,059 Robert H. Park 660
Heinrich Lenz 5,551 Joseph Saxton 433
Ányos Jedlik 5,237 Paul-Gustave Froment 329


  1. ^ a b c d e f g h i j k l m n o p q r s Doppelbauer
  2. ^ a b c d e f g Drury
  3. ^ a b c d e f g h i j k l Electropeadia
  4. ^ a b c d e f g h i j k l m n o p Multon
  5. ^ a b c Martin
  6. ^ "Francois Arago". Encyclopedia Britannica. 
  7. ^ a b c d e Vučković
  8. ^ a b c d e f g h i j k Michalowicz
  9. ^ a b c d e Boursin
  10. ^ Kenyon
  11. ^ Baily
  12. ^ Mora, J. F. (2006). Genios de la ingeniería eléctrica : de la A a la Z. Madrid: Fundación Iberdrola. ISBN 84-609-9775-8. 


Current slap-dash editing not worthy of Wikipedia[edit]

The current slap-dash changes being made to Electric motor is unworthy of Wikipedia, the proof of the pudding being in the eat.

What is Electric motor article needs should be measured for performance.

For example, the views of the Torque and speed of a DC motor article, which was revamp over the weekend as shown below, and which has been languishing for several years, went up nearly 91% overnight from Monday (390 views) to Tuesday (746 views). This is the kind of performance needed of electric motor; no amount of careless editing can make up for measurable performance.Cblambert (talk) 17:27, 13 March 2013 (UTC) +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Unfortunately, before you get a really bad case of hit-itis, you should know that, with rare exceptions, hits are nothing much to do with quality, you will nearly always find that page hits are very much more to do with how well the article is linked; an article can be complete garbage and receive lots of hits, or be brilliant and get no hits. It's mostly how it's linked to, and that's pretty much also how the search engines ranks it, not nearly so much what is in the article (unfortunately).Teapeat (talk) 20:29, 13 March 2013 (UTC)
I haven't checked at all, but presumably you will have added links to those articles for them to go up like that.Teapeat (talk) 20:29, 13 March 2013 (UTC)

Reverting to deletion of Torque and speed of a DC motor article. I stand by the jist of my argument. Recent changes are unprofessionally done. Compare ]]Electric motor with Transformer. Long way to go.Cblambert (talk) 02:40, 14 March 2013 (UTC)

Pecker head[edit]

Cursory googling shows that the entry at pecker isn't vandalism: this is a term used by American electricians in conjunction with electric motors. However, this page lacks any mention of it, its British equivalent "T-box", or its Canadian equivalent "pothead". Granted, all of those are slang and could be left to Wiktionary. However, there's no explanation whatsoever of even what a "motor terminal box" is. Someone please emend the page so it at least includes the basic terminology. — LlywelynII 07:21, 30 June 2014 (UTC)

motors with permanent magnets[edit]

Several wikipedia articles (such as, for example, Zumwalt-class destroyer) mention "PMM", "permanent-magnet motor", "permanent-magnet electric motor", and similar phrases.

Linkifying those phrases generally leads people to one of "Synchronous motor#Permanent magnet motors" or "Brushed DC electric motor#Permanent-magnet motors".

Is there an easy way to tell while I'm linkifying those phrases which of those two destination articles is the correct one for that particular article's context? --DavidCary (talk) 18:41, 12 August 2014 (UTC)

Probably not. If you can see that the motor is powered by AC, the synchronous motor link is probably appropriate. If you can see it's powered by DC, then the "brushed" permanent magnet motor might be meant. Unless it's got some clever solid-state driver? --Wtshymanski (talk) 18:59, 13 August 2014 (UTC)

Discussion of proposed merge of Reciprocating electric motor to here[edit]


Article appears to have been improved and there is no consensus for either proposed move.--agr (talk) 11:18, 6 October 2016 (UTC)

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

  • Support as proposer. Stub article on a narrow subject, unlikely to ever warrant an article of its own. It can live here until that changes. Jeh (talk) 22:02, 20 March 2015 (UTC)
  • Support - too short for a stand-alone article. - Ahunt (talk) 23:07, 20 March 2015 (UTC)
  • oppose merge and delete One is sheer WP:MADEUP crap, the other a technology vital article. We should not contaminate one with the other. Andy Dingley (talk) 20:45, 22 March 2015 (UTC)
    • Well, someone PRODded it (and I PROD2'd it) but some well-meaning person objected that the subject could not have been made up, as there are references. I concur re the "made up crap" in the content at the existing "article" (I use the term loosely), but I am assuming it would be fixed. There is such a thing as a "reciprocating electric motor", and the refs are valid even if the text is not. Perhaps the best thing would be to just put proper content on this subject (no more than a few sentences) into Electric motor, then I'll withdraw the merge prop and we'll let the AFD proceed to its rightful end. Jeh (talk) 22:03, 22 March 2015 (UTC)
      • There is no more any such thing as a "reciprocating electric motor" than there is a "wiggly springy magnet motor". In no way is this "a standard type of motor". The one source in that article is a Juggalo-science site that is "somewhat deficient" in meeting WP:RS, to say the least. This is also rather far from WP:N as a topic. Andy Dingley (talk) 00:37, 23 March 2015 (UTC)
        • I don't think it is true to say there is no such thing as a reciprocating electric motor. Some early electric motors were reciprocating, with a connecting rod and crank like a steam engine. There are some examples here [6] Biscuittin (talk) 02:04, 23 March 2015 (UTC)
          • So what? Those are not even mentioned in this current article. It certainly doesn't imply coverage of them.
It is trivially obvious that any electrician from the mid-19th century to today could contrive some sort of "motor" in which "electricity" (electromagnetic attraction, cross product or even electrostatics) could be said to involve some part that "reciprocates" in some vague manner. However that is neither interesting, significant, nor WP:Notable until multiple independent sources pay some sort of attention to it. That is not what has happened here. Andy Dingley (talk) 02:14, 23 March 2015 (UTC)
BTW - why are you so keen to defend an article like this, yet you're simultaneously out to delete magneto (generator)? Andy Dingley (talk) 02:16, 23 March 2015 (UTC)
Please have another look at Talk:Magneto (generator). I don't want to delete the article, just re-name it. As regards Reciprocating electric motor, I think the article is basically describing a linear motor [7] Biscuittin (talk) 02:25, 23 March 2015 (UTC)
I have proposed a merger with Linear motor. Biscuittin (talk) 12:41, 23 March 2015 (UTC)
Well today you've switched to renaming the article to a new invented term, "high power magneto", that makes no sense and has no pre-existing use to justify it. This is still not how disambiguation in article titles is handled.
As to this article, then yes - there are obviously ways to make an "electric motor" that involves "reciprocation". These are not implicitly notable though. They have to demonstrate WP:GNG, same as anything. If the Acme Reciprocating Compressor Co. makes a device based on a linear motor and a spring (as seems to be your claim here) then we still shouldn't have an article on it, until independent secondary sources start writing about it.
Your desperate scramble to save this article by merging it isn't being resisted because you've picked the wrong target, but because it's not an article that should be saved.
This article doesn't even have that much credibility. It's about some home-made idea that an electric motor should work like a steam engine. WP:MADEUP bollocks the lot of it. It probably can be, but just because one person did it and put it on youtube, that doesn't make it notable - and for very good reasons. Andy Dingley (talk) 12:56, 23 March 2015 (UTC)
I am not making a "desperate scramble to save this article". I am just trying to be fair to the author. I think the deletion proposal is premature and the article's author should be given a chance to improve it. Biscuittin (talk) 17:08, 23 March 2015 (UTC)
I've always got a long tolerance for saving poor articles on good topics. However this is an article that's clearly pointed at a one-off "Hey kids, Fun with Magnets!" model that completely fails to show independent notability. We are not here to list every time a youtube channel uses the considerable strength of a modern rare earth magnet to demonstrate trivial and inefficient power production.
One might write an article on the short-lived solenoid and ratchet or rocking beam motors produced by Daniel Davis of Boston in the 1830s. These are real, existed and have some recorded footprint. However they were also obsolete by the 1840s and Froment's mouse mill motor, still an attraction motor but directly rotating. What is still clear though is that this article hasn't been based on these, but on the youtube demo with the unfathomable "magnetic cam". Andy Dingley (talk) 17:48, 23 March 2015 (UTC)
What are you talking about? There are five references and none of them links to YouTube. Biscuittin (talk) 19:11, 23 March 2015 (UTC)
  • MERGE TO LINEAR COMPRESSOR Linear_compressor is the same topic; so it's a duplicate of that. It's just a linear motor used to compress stuff, it's not a special type of electric motor.GliderMaven (talk) 23:03, 23 March 2015 (UTC)
Ridiculous. It is neither a compressor nor a linear motor. Yet again, your technical ignorance and still happiness to make nonsensical assertions despite borders on WP:CIR. Andy Dingley (talk) 23:24, 23 March 2015 (UTC)
Do please read the references at Reciprocating electric motor. I had a look at WP:CIR and saw this: "Some editors hold personal opinions so strongly that they cannot edit neutrally and collaboratively with other editors". Now who does that remind me of? Biscuittin (talk) 02:19, 24 March 2015 (UTC)
Well, I went this page: [8], which is linked as a reference from linear compressor and it disagrees with you, and I believe it, and not you.GliderMaven (talk) 02:36, 24 March 2015 (UTC)
I agree with you, GliderMaven, my comments were aimed at Andy Dingley. Biscuittin (talk) 10:22, 24 March 2015 (UTC)
I have knocked the article into shape. It still needs further work but I think it can now stand on its own so I request that the deletion and merge tags be removed. It is not just about linear compressors, it is also about machines with crankshafts. Biscuittin (talk) 12:13, 24 March 2015 (UTC)
They're not a distinct type of electric motor, they're just a linear motor. Connecting a linear motor shaft to a crank doesn't make it a different type of electric motor, it's just a motor on a crank. The linear compressor is a different compressor type, but that already has its own article.GliderMaven (talk) 13:50, 24 March 2015 (UTC)
We are really getting bogged down with definitions here. I think the article should be given a chance because of Wikipedia:Please do not bite the newcomers. Biscuittin (talk) 15:13, 24 March 2015 (UTC)
We have not merged Free-piston engine with Piston engine and that is analogous. Biscuittin (talk) 15:17, 24 March 2015 (UTC)
Wikipedia bases where things go on definitions. And there is absolutely no connection with a free-piston engine in this context; a combustion engine is neither a pump nor an electric motor. Your faulty argument is getting bogged down, yes.GliderMaven (talk) 16:22, 24 March 2015 (UTC)

Keep the article and nom merge, it is a diffrent type of electric motor, it could have a sumary here and a link to the main article. Doorknob747 (talk) 17:02, 24 March 2015 (UTC) there are so many refs and article has expanded. Doorknob747 (talk) 17:02, 24 March 2015 (UTC)

Thanks Doorknob747. We now have lots of references to "Reciprocating electric motor" so it is an established concept. GliderMaven, the relationship between reciprocating electric motors with and without cranks is the same as the relationship between piston engines with and without cranks. I think the opposition to this article is largely based on prejudice and I refer to Wikipedia:Don't be prejudiced. Biscuittin (talk) 19:11, 24 March 2015 (UTC)
I asked some admin and they said the people who support this merge and deletion are violating Wikipedia:Don't demolish the house while it's still being built 100%. They said if they do delete it I just report to the admin and they will revive the page, they did say though that the article can only be protected under this for a month after which the thing u said will only be protecting it. Doorknob747 (talk) 20:20, 24 March 2015 (UTC)
The proposal after reading votes, some votes violate, Wikipedia:I just don't like it.Doorknob747 (talk) 20:27, 24 March 2015 (UTC)
Well done Doorknob747. I think we are making some progress. Biscuittin (talk) 23:16, 24 March 2015 (UTC)
Merge would not be "demolishing", and "I don't like it" is about opinions unsupported by reasoning. (That you don't agree with the reasoning is irrelevant.) Jeh (talk) 16:20, 25 March 2015 (UTC)
  • Redirect to Linear motor. Sincerely, SamBlob (talk) 10:26, 25 March 2015 (UTC)
    • That would work, if the protectors of Electric motor just won't have it. It's not significant enough for an article of its own. Jeh (talk) 16:20, 25 March 2015 (UTC)
    • Can you clarify (in the stated terms of this article) whether linear motors use either cams or cranks to produce their rotation?
Also linear compressors don't use linear motors. The device they use is more like a linear force motor (see torque motor for a WP analogy, albeit semi-rotary) with a restoring spring. Andy Dingley (talk) 16:24, 25 March 2015 (UTC)
As you know full well, force motors don't do work. A compressor does do work. A compressor has a true motor, in this case a linear motor.GliderMaven (talk) 18:08, 25 March 2015 (UTC)
If we can't agree on the technical details, we can't make a sensible decision on what to do. I request that you leave the article alone and let Doorknob747 and me develop it. Biscuittin (talk) 18:25, 25 March 2015 (UTC)
That's not how Wikipedia works.GliderMaven (talk) 18:43, 25 March 2015 (UTC)
"As you know full well, force motors don't do work." Maybe in theory, when working against a rigid stop. However in practice they're against something deliberately compliant, in this case a spring. Andy Dingley (talk) 19:02, 25 March 2015 (UTC)
Simply acting against a spring in and of itself isn't normally considered to be work, a spring is an energy storage medium, and has very low losses. Whereas using a linear motor in a linear compressor which is definitely doing useful work.
And if they're actually doing significant work, then they are, by definition, not force motors, they're motor motors.GliderMaven (talk) 19:44, 25 March 2015 (UTC)
  • Oppose merge. There is now sufficient material in the article for it be standalone. There are book sources on this subject. [9] discusses a modern design. [10] mentions a medical pump application. [11] mentions an application used by Edison. I also agree that this is completely separate from linear motor and oppose the merge there. SpinningSpark 22:57, 25 March 2015 (UTC)
Thank you, SpinningSpark. Biscuittin (talk) 10:07, 26 March 2015 (UTC)
  • Oppose merge. I agree with SpinningSpark. I think the article is long enough to be its own. Just link it to Electric Motor — Preceding unsigned comment added by Pandg2 (talkcontribs) 20:56, 22 March 2016 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Motor with carbon brushes and induction on one shaft?[edit]

I have two old Asko washing machines which have a quite unusual type of engine: a Siemens hybrid one. It has a induction motor part in the middle and on the non-drive side end a carbon brush part, complete with collector and all.

Question is: what are these engines called? I know Miele had a 2 in 1 engine design for their very, VERY old 400-series machines (the Muet, which had two pairs of brushes for washing and spinning and thus also two collectors) but I can't find anything related to it on Google.

I guess the name is just "induction engine with brushes for spinning" --2001:1C03:1600:4900:6931:B0E4:24E4:2A03 (talk) 04:41, 28 February 2016 (UTC)