Re: Why do stepper motors lose their magnetism when disassembled?

As I said, I can't argue with the fact that many have come to grief
disassembling a stepper motor. I guess I got lucky. I do vaguely
recollect that when I did the disassembly I was using a simple minded
stepping driver that did not chop the applied current and I could
vary the applied current to way above the rating on the winding (1
amp). Again my vague recollection is that when first re assembled the
motor did not exhibit significant cogging but after setting up in the
driver circuit it behaved as expected and currently it has been
working on my mill for the past 4 years. Perhaps the steady applied
DC re magnetized the rotor, although if this did happen how come the
rotor is not equally easily demagnetized when in normal service?

Mike