Talk:Synchronous motor

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[edit] Request for expansion

  • I'd like to see more information on the control of a synchronous motor/generator. What's the amount of current you'd like to send through the powering magnets, how do you calculate it?
  • There are many ways a synchronous motor can be constructed, an explanation with pictures will be useful.
  • How do you start it? It can't be just turned on. It has to be either brought up to speed, and then the power can be turned on, or it has to be controlled using power electronics which control the frequency. Or alternatively one could start without current through the rotor, and use an impedance instead, it would be a regular AC motor, and then switch to synchronous when it's brought up to speed. If someone could elaborate on this subject, please add it to the article. —Preceding unsigned comment added by Aphexer (talk • contribs) 09:11, 12 January 2008 (UTC)

[edit] Content removed

I removed the following "disadvantages" section. The points made are only valid for specific variants and are not otherwise generally applicable.

A different section should be started to discuss

  • high power synchronous motors
  • synchronous condensers

due to their peculiarities.

[edit] Disadvantages

  • They are fundamentally much more expensive than their squirrel cage counterpart due to their particular construction.
  • A synchronizing equipment must be installed in order to apply current to the rotor windings when the motor achieves 95-97% of its synchronous speed.
  • They are often used in high-power applications (above 1 000 HP), when proper starting techniques must be used in order to minimize the undesirable effects on the electric network due to the large amount of current required. This is not unique to synchronous machines, though, as any motor will draw 5 to 6 times their nominal current during the starting phase.

Choppingmall 00:07, 25 August 2007 (UTC)


I also removed the following:

[edit] Construction

The stator of a synchronous motor is not different from a squirrel cage motor, as it is composed of windings disposed to provide a rotating magnetic field when alternating current is applied. The rotor, though, is designed to provide a static field by itself to lock with the stator's. This is obtained with a permanent magnet in the case of small motors and DC windings on bigger units. A small generator, called an exciter, is sometimes mounted on the shaft of high power motors in order to provide 3-phase current, which is rectified and fed in the motor rotor windings.

The principle of having the rotor provide a static field (generated by windings or permanent magnet) which "locks" with the stator's is a really good description -- but the rest is not generally applicable. A section should probably be made to describe "typical" construction, but acknowledge that there are other ways of doing it. Remember that high power synchronous motors are relatively unusual compared to small ones, so don't generalize based on their characteristics.

Choppingmall 00:26, 25 August 2007 (UTC)

[edit] 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.[1]

I wonder if the four IP addresses listed above have any connection... Naw, couldn't be. [2][3][4][5] 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) 18:20, 28 December 2007 (UTC)