Thermal fatigue strength data of enamel cu wire

We are using enamel copper wire typically in 16 to 25 SWG wire sizes, used in armatures of small DC motors.We are experiencing fracture of the wire close to the commutator after being in service, although the basket between the armature and commutator is restrained from flinging by potting with epoxy.Seeking information on similar experiences and fatigue data available

kindest regards,
N.Balachanderan

There are two very good magnet wire engineering specialists that monitor the Forums and answer questions. I have been in contact with one of them but he is extremely busy at the moment.

Sorry for the delay but please have patience. Thank you.

Regards,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

BalachanderanN,

Without seeing the wire, my first thought is that since you are saying that the wire cannot flex but it is failing near the commutator, I think that the problem is probably in the coil winding process. If the wire is not hitting anything, and it is restrained by the epoxy, I would take a good look at the coil winding process to see if the wire is being damaged.

richard