Originally Posted by
cplus
not in my experience. I’ve tested the individual components (stator, rotor and timing board) of motors of 2 reputable brands for well over 100 “identical” samples of both groups when brand new and then for a very high portion of them, as used units as well.
Stator resistance can vary HEAPS out of the factory. Easy to see 1milliohm per phase (tab to collector) between two samples.
Rotors I have found to be much closer out of the same batch. Typically it’s 25gauss or so variance.
25 gauss is around 1.5% typically, 1milliohm is more like 5% on a 17.5 - and as said, the latter is more common to see.
Sensors vary a heap too - but you can “tune” around it.
I'm surprised to see you're only getting 1.5% variance in rotors, I've seen much larger variance. However, even with 5% stator IR variance, I wouldn't expect that to lead to a 50% higher current draw.