Talk:Motor capacitor

Spam links

I don't know how to use this, so let me just leave a note for editors here: the links at the bottom are 100% pure spam. I clicked through hoping to read some more about ac motor capacitors and got to colored pages selling capacitors...it looks terrible on an encyclopedia to allow stuff like that. —Preceding unsigned comment added by 189.6.8.191 (talk) 03:25, 22 June 2010 (UTC)

I read the above comment about the links at the bottom being "pure spam". I have just stumbled upon this article while trying to learn more about the characteristics and differences between start and run capacitors. There are currently two links of five which this quote can be talking about. One is the Best Buy Heating and Air Conditioning link, strangely on a page of a 45+5 mfd dual run capacitor. The page is very informative and the one of the fes links I can Google on the web regarding the wiring of the capacitors (herm, c, fan terminals). The other link I see here is from Arnold Service and the best I can find on the web regarding swapping values for capacitors, and the entire FAQ, i.e., in this case the referenced unacceptability of replacing a capacitor of 440V with one of 370V, which is not obvious considering the line voltage is typically 240V and one would assume this is ok. Although the pricing on the first reference for their capacitors is at the far high end of retail, the information contained is highly informative. I would prefer to have a more authoritative source and not a commercial one, but until then, these statements are essential for a confused reader trying to understand the basic information about using these capacitors in their typical applications. I hope this article is greatly expanded as the information it contains is almost impossible to Google due to what I would describe as the HVAC good-ole-boy network trying to keep basic information out of the hands of inquiring minds. Example: The $67 USD capacitor Best Buy Heating and Air Comnditioning linked to has a trade price to “technicians” of $6 - $15 USD (if you can manage to get into "trade price" sites) and is available for about $22 on the Arnold site and the only parts store in my large city selling it to the public. It would typically cost about $130 if installed by a “technician”, though I’ve read on complaint boards about abuses going up to $500 for parts of trade costs all well under $15. The technician will have already charged for a service call to diagnose the problem (about $100), and this is basically a scam of double charging customers commonly practiced by "technicians" established or not. The referenced $130 is simply to swap out the part after a customer has paid for their diagnostic expertise – which in my case is no more than a 30 second job – so essentially it is the price of the $6 - $15 part after an already expensive service call. Prices will obviously vary in different markets for “technician” costs and it is not obligatory for “technicians” to be trained by compressor/motor manufacturers, just to take an unregulated course and apply for a state license which does little to insure the “technician” will act honorably by replacing the correct part rather than doing something an inquiring mind cannot audit using a neutral source like Wikipedia. I have never contributed to this article and wish a better developed and more authoritative article could be made on start/run capacitors as this one is still very weak but the best I can find. The Louisiana course link is the only non-commercial link and the source cited by them is a refrigeration handbook (1988). Hopefully that book could be further referenced directly for this article. —Preceding unsigned comment added by 98.82.119.63 (talk) 13:29, 28 July 2010 (UTC)

Created

The article "Motor capacitor" was created on 24-Sep-2008 by long-term user Wikid77, by paraphrasing 4 sources but inserting reference footnotes to support the text. It is separate from the general article for "capacitor" to allow defining 7 related terms as redirected titles in the top lede section: dual capacitor, run capacitor, start capacitor, dual run capacitor, round dual run capacitor, and oval dual run capacitor. Those terms are specialized types of capacitors that are treated as a sub-category of applied capacitor technology. No other article on Wikipedia had described those types of capacitors, and they involve specialized details not applicable to other capacitors. -Wikid77 (talk) 18:55, 24 September 2008 (UTC)

• NOTE: The first 2 revisions of the article both have history edit-summaries stating they are the "created" original, due to temporary wikiserver problems ("Wikimedia Foundation error") during a whole hour, which made the 2nd revision seem to be the first creation of the article. -Wikid77 (talk) 19:20, 24 September 2008 (UTC)
• I have decided to NOT define redirection titles for "round dual run capacitor" and "oval dual run capacitor" because both titles had only about 200 Google hits, and readers could find them by wiki-search. So those will be 2 less of the current 2.6 million (2,563,483) Wikipedia articles. -Wikid77 (talk) 19:43, 24 September 2008 (UTC)

Article about motor capacitors not motors

The article was tagged for possible deletion, using "{{dated prod}}", on 2008-09-24 at 17:23, for the reason:

"Already covered at AC motor#Capacitor start motor and AC motor#Permanent split-capacitor motor. Some material here might better be added to AC motor."

However, the article is NOT about motors, but rather capacitors outside those motors: no detailed description of various motors is included, since the focus is the capacitors rated by microfarads and voltage. The common word used is "start" as in the term "start capacitor" rather than "start motor" as appears in the other article, "AC motor". -Wikid77 (talk) 18:55, 24 September 2008 (UTC)

• 24-Sep-2008: I have untagged the article for deletion, based on the above explanation that the article subject is about "capacitors" not "motors that use capacitors" as described in the other article. -Wikid77 (talk) 19:06, 24 September 2008 (UTC)

AfD debate requests wider scope

26-Sep-2008: The article was tagged for "AfD" (article for deletion) at 04:15, 25 September 2008 (UTC). The discussion included concerns that the text in the article was focused too much on HVAC issues, with several reference sources related to HVAC sales websites. There is a very wide variety of motors that use various capacitors, and the article should be expanded to cover those details. The intent of the article has been to provide wide coverage of the subject, but also address concerns of general readers, such as the use of capacitors in A/C compressors or ceiling fans, focused on the role of the capacitors in those systems. -Wikid77 (talk) 22:51, 26 September 2008 (UTC)

Unit of capacity?

In the text, mfd is used as a unit for capacity, equalling microfarads. Why can't the official µF unit be used here (µ mu being prefix for a millionth, F being Farad, the unit for capacity)? (ArticCynda (talk) 22:38, 16 November 2009 (UTC))

I would tend to leave that alone. Its a quirk of the trade. AC equipment isn't a new field. There was no µ (greek mu) on an english typewriter, the abbreviation mf is used for a vulgar expression, and so mfd went in catalogs and on parts lists and most importantly, typewritten purchase orders. Once done, there hasn't been a sufficiently compelling reason to change. There's very little overlap between AC motors and other electronics communities that use µF. — Preceding unsigned comment added by PolychromePlatypus (talk • contribs) 22:59, 27 October 2012 (UTC)

The lack of a mu key on a typewriter (or computer) doesn't stop people using "u" very widely. The HVAC field might be an old one, but motor caps are now widely (though not universally) labelled with "uF". So it's appropriate for an article such as this to use the proper units. Gwideman (talk) 00:22, 22 February 2019 (UTC)

Wrong Link to German

The German links to an asynchronous motor, not a motor capacitor. — Preceding unsigned comment added by 109.238.72.226 (talk) 08:07, 3 April 2012 (UTC)

The correct link is: http://de.wikipedia.org/wiki/Leistungskondensator#Motorkondensator [[1]] --Elcap (talk) 00:09, 4 April 2012 (UTC)

Replacement tolerance information incorrect

The statement "replacement capacitor should be within 5% ..." etc. is well meaning but incorect. This type of capacitor is not manufactured to a 5% tolerance, and are usually available in increments of more than 10%. Furthermore, the capacitance changes with; the terminal voltage, age, and temperature. Motor cicuits aren't very sensitive, a 20% change in run (or start) capacitance results in less than a 10% change in breakdown (or starting) torque. Making sure the temperature range is adequate and that the safety venting can function (e.g. the style with blow out terminals mounted neither to hold the terminal rigidly in place nor so as to allow a live ejected terminal and lead to contact other conductors.) The correct answer is that the replacement capacitor must meet or exceed the circuit requirements, and if you aren't able to determine what those are replace with the same type, mounting style, capacitance, voltage rating, temperature range, and safety features, or better. My source reference for this information is me, an EE with long experience. No manufacturer will ever put anything other than "replace with geuine (OEM) parts" in writing because a lawyer will argue that this can make the replacement part supplier a co-defendent when a defective product injures a consumer. — Preceding unsigned comment added by PolychromePlatypus (talk • contribs) 22:43, 27 October 2012 (UTC)

MFD?

Some people (at least used to) use MFD as uF. Maybe note that in article. I thought it might mean millifarad. 71.139.160.208 (talk) 16:58, 27 March 2016 (UTC)

Capcitors big enough to be measured in millifarads are rare, m is convenient (especially on typewriters). It has been used for both, most commonly for micro-, because the context is generally clear. MFD was common for millifarads (on things the size of milkbottles) but I've never seen it (uppercase) for micro-. Andy Dingley (talk) 17:46, 27 March 2016 (UTC)

Thank you for your edit! 71.139.160.208 (talk) 04:29, 30 March 2016 (UTC)

And as a counterpoint, from my experience, the use of mfd or MFD was rampant to mean microfarad, through the 70's at least, and probably depends on industry. To the point that mmfd was used for pF. The capital "M" means Mega in the SI system, yet MF never means MegaFarad as there are no such capacitors. And contrary to Andy Dingley's comment, I've never seen lower case "m" mean milli when applied to capacitors. I have seen recent start and run caps marked with uF, and others STILL marked with MFD (meaning microfarad). Gwideman (talk) 00:18, 22 February 2019 (UTC)

Suddenly an example of a run capacitor within the start capacitor section.

Suddenly an example of a run capacitor within the start capacitor section.

Start capacitors have ratings above 70 µF, with four major voltage classifications: 125 V, 165 V, 250 V, and 330 V. Examples of motor 
capacitors are: a 35 µF, at 370 V, run capacitor, or an 88–108 µF at 250 V start capacitor.[1]

Jidanni (talk) 11:58, 16 June 2018 (UTC)

Run capacitors are also 250V

I found a

CBB20 Motor Run Capacitor 30uf 250V AC for Rigid Sump Pump 1/2 Hp

proving run capacitors are also 250V. Jidanni (talk) 13:11, 16 June 2018 (UTC)

"Levels of protection"

§ Failure mode says:

IEC/EN 60252-1 2001 specifies the following levels of protection for motor run capacitors:

• P0 - no protection;
• P1 - fail open circuit or short circuit;
• P2 - fail open circuit only.

I added a hidden comment, as follows:

<!-- But what do these "levels of protection" mean in practice to the average person? -->

I honestly have no idea how this information would help our Wikipedia readers. Surely information must be at least potentially useful to have any value? yoyo (talk) 09:41, 7 December 2019 (UTC)

References

Toxic Hazards

I just added a section on PCBs in older capacitors. I think the refernce link work but lacks a date etc. I hope someone can straighten out this referece for me, i have little experienc with wiki references. — Preceding unsigned comment added by 100.40.9.102 (talk) 18:15, 10 September 2020 (UTC)

Electrical Symbols

Anyone have the electrical symbols for run vs. start caps? E.g. one I am replacing has two vertical parallel lines, with two horizontal parallel arrows pointing in opposite directions, upper arrow to the right. Guessing it's a non-polarized marking, however it prompted the thought that having the schematic and electric motor related symbol conventions would be valuable. 2601:601:9900:11A0:EC5F:DEDD:6699:35A1 (talk) 23:59, 15 April 2023 (UTC)