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Anonymous Poster #1

Commutation Compensation Winding in DC Motor

10/21/2018 3:28 AM

Dear All I am having a DC motor of 2X1900 KW which are connected in series both of these motor are having a third winding called commutation compensation winding.If a Dont give supply to this winding is there any chances that my field weakening position changes and Armature voltages goes beyond mentioned armature voltage in one direction and less in other direction.Motor data Armature current 3425Amp, Armature Voltage -1200V,Speed-320/855,Field current 155Amp/34 Amp,Field Voltage 440, Compensation winding Current 45Amp Voltage-220V
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TonyS
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#1

Re: Commutation Compensation winding in DC Motor

10/21/2018 7:52 AM

There's every chance you'll ruin the commutator.

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HiTekRedNek
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#2

Re: Commutation Compensation Winding in DC Motor

10/21/2018 9:17 AM

Here is a link that will help you understand the function and importance of a compensation winding.

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Rixter
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#3

Re: Commutation Compensation Winding in DC Motor

10/21/2018 9:48 AM

There is an optimum position for brushes in a commutated DC motor to minimize sparking. This optimum position changes when the load varies or the motor is reversed. To reduce this shift, a commutation compensation winding, which carries the armature current, is used to cancel out the field distortion.

A. Cross section of DC motor with compensation windings. A = armature windings, C = compensation windings, F = field windings, R = rotor (armature), S = stator (field).

Here is a good description:

https://en.wikipedia.org/wiki/Compensation_winding

https://www.electrical4u.com/commutation-in-dc-machine-or-commutation-in-dc-generator-or-motor/
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rwilliams
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#5
In reply to #3

Re: Commutation Compensation Winding in DC Motor

10/22/2018 12:27 PM

Except that the winding current rating listed by the OP does not match with any normal commutating coil wiring, so maybe separately excited compensation, to keep large cross-section area copper for this good sized motor?
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Dennis R. Levesque
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#4

Re: Commutation Compensation Winding in DC Motor

10/21/2018 11:35 PM

Whoah..wait a minute... "....If I Don't give supply to this winding..."?

This winding is not one that you just "plug in" to a power supply. It has to be tied into the motor somehow (either the rotor or field current or some controller that senses the load on the motor). If you disconnect it from its original supply (for some reason), you'll get into more trouble than trying to fix the original supply. Are you trying to avoid repairing the original circuit?

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TonyS
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#6

Re: Commutation Compensation Winding in DC Motor

10/23/2018 12:30 AM

I was under the impression that the full armature current pasted through the commutation compensation winding. So as Mr. Levesque pointed out, you can’t simply disconnect this winding. You could short it out but then you would have to adjust the brushgear commutation point manually, not something I’d recommend. I’ve had experience of brushgear being out of line, the firework show was impressive frightening.

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Dennis R. Levesque (1); HiTekRedNek (1); Rixter (1); rwilliams (1); TonyS (2)

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