Re: [CAD_CAM_EDM_DRO] operating temp of stepper motors

In a message dated 1/24/2003 8:56:04 PM Central Standard Time,
kenargo@... writes:

> Should I be worried about this temp or is this normal?
>

Ken: Someone else "in here" with much more wisdom than I will hopefully
answer you more responsibly than I, but I will at least throw out MY 2¢
worth:

That is above the "design limit" for "Class A" insulation, which most
non-military steppers are, I think. They will probably have relatively short
lifespan at 150°F. When you say "parallel", do you mean these are 8-wire
motors, and you have them connected as bipolar? And the current PER winding
(each of two per motor) is 4+ amp? That is quite high for "continuous" for a
Size-23!

Are they RUNNING most of the time, or at stand-still much of the time? If
the latter, ONE thing that can be of amazing help is the Gecko drives, as
they "drop back" to 1/3 current at stand-still, after, what, two seconds?
This keeps MY Size-34 motors just-warm!

General "rule of thumb" is, "If you can't hold your hand tightly on the motor
for more than ten seconds without quite unpleasant discomfort, or the paint
melting into the folds of your finger-prints, it is too hot!"

Jan Rowland, old Troll


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