hello all,
I trust that you are well.
Terry, you are quite right about the growler test, this test is in place here. The bar to bar test is used when a motor enters the workshop for repairs. The stator and armature are seporated and the bar-to-bar test is sort of the first electrical inspection on the armature.

Just to mention the ratings of these motors, some of them are rated at 800V/600A so yes, they are rather large.

Kai, for the millivolt discussion, the resistance of 0.0148 ohms is that of the entire armature, so yes there will be a 1.48V drop but this across the entire armature. Considering the commutator consists of 270 bars, this should lead to a 5.48 mV drop across each pair of bars, hence the millivolt range.

I am leaving today to perform a test at one of our workshops, I will take the readings and share them with you.

Thank you all,
sun