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Failure in Small DC Motors

Failure in Small DC Motors

Failure in Small DC Motors

(OP)
Dear Friends

Atached you will find a picture of the armature winding of this small motors.
 
We was repair some  DC electric motor of 2.2 KW, this one are working in very severe ambients in compresors, electric cranes and are exposed to high vibration, this motors are working in S4 duty and in at least 90 % are working above rated power value.
 
In the begguinning we found a failure due to the  breakdown of the wires welded in the conmutator,and the welding material loose too due to this today we are ussing tin at 95 % and not 70 %.Today  the welding material stop to melt but the wires stilll brokes.
 
What do you think is happening here ?  
 
Thanks and best regards

Petronila

RE: Failure in Small DC Motors

How fast does it spin?  You may need to support the wires if the centrifugal forces are large.

RE: Failure in Small DC Motors

You may want to consider VPI'ing the armature windings.

RE: Failure in Small DC Motors

If you are operating above rated power, that's your problem.  It looks to me like there is significant heating where the wires meet the commutator.  I don't know if this is from welding or the connection might be higher impedance causing heating.

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If it is broken, fix it.  If it isn't broken, I'll soon fix that.

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