Rotation of Neutral Axis due to Armature Reaction in Brushed DC Machines

[JukeBox11]

Hi,

I am working on a project which I need a theoretical equation of how much armature reaction rotates the electrical neutral axis in brushed DC generators/motors. I am thinking it will be dependent upon armature flux/current, windings, etc. If anyone can help me out that would be great.
Cheers.

 

[waross]

Well designed inter poles or commutating poles will cancel out most of the shift.

Bill
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"Why not the best?"
Jimmy Carter

 

[JukeBox11]

Thanks Bill, you're right. But is there any way to quantify the rotation of the electrical neutral axis due to armature reaction (with or without taking comm poles and interpoles into consideration)? By an equation or any other means?

 

[Skogsgurra]

Since the rotation is proportional to the torque, the angle will be roughly proportional to armature current. If there are compensation windings in the pole-faces, the rotation will be close to zero.

Armature reaction (weakening) sets in when the angle has moved the flux so far that the pole face edges saturate. That effect is sometimes confused with rotation of the neutral axis.

Not so sure if interpoles/commutation poles influences the main field other than locally.

Gunnar Englund

http://www.gke.org

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