Previous in Forum: Panel to Panel Clearance in a Switchgear Room   Next in Forum: Dry Type Transformer Failure
Close
Close
Close
6 comments
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

Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
United Kingdom - Member - New Member

Join Date: Aug 2010
Location: Resting under the Major Oak
Posts: 4348
Good Answers: 180
#1

Re: Commutation Compensation winding in DC Motor

10/21/2018 7:52 AM

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

__________________
The reports of my death are greatly exaggerated.
Reply Score 1 for Good Answer
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 6284
Good Answers: 245
#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.

__________________
"A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience"
Reply
3
Guru

Join Date: Apr 2010
Location: About 4000 miles from the center of the earth (+/-100 mi)
Posts: 8880
Good Answers: 1012
#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/

Reply Good Answer (Score 3)
Guru

Join Date: Jul 2016
Posts: 1014
Good Answers: 69
#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?

Reply
2
Guru

Join Date: Apr 2017
Location: Southern Illinois
Posts: 620
Good Answers: 13
#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?

__________________
Science is the "cookbook" for making things.
Reply Good Answer (Score 2)
Guru
United Kingdom - Member - New Member

Join Date: Aug 2010
Location: Resting under the Major Oak
Posts: 4348
Good Answers: 180
#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.

__________________
The reports of my death are greatly exaggerated.
Reply
Reply to Forum Thread 6 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

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

Previous in Forum: Panel to Panel Clearance in a Switchgear Room   Next in Forum: Dry Type Transformer Failure

Advertisement