RE: [CAD_CAM_EDM_DRO] safe temp for steppers ?

Speaking of motor heating makes me think that anyone who has not read
the Gecko Drive stepper white paper ought to as it has a very good
section on heating.

In regards to heating with a stepper, if the motor is not getting hot
you are driving it far below what the motor is capable of in regards to
power output. Of course many of us make that choice knowingly and prefer
to have cool motors than the maximum performance. There are 2 causes of
heating. One is the amperage you drive the motor at. The closer to the
specified maximum you get the hotter the motor will run. All the
manufacturer spec amperages I have seen will give you a hot running
motor as they are specifying a current level that will give the maximum
performance. If you use idle current reduction (which all the Gecko
stepper drives for the last year or so have), you can limit the heating
due to current when the motor is not moving, but if at max current it
will heat up once you start moving it. The other cause of heating is the
over voltage we drive the motors at. The higher the over voltage you use
the more heating you will get and this heating mode can only be reduced
by lowering the drive voltage. The 25X figure that is so often quoted is
based upon Mariss's experience that most motors will run at the top of
their thermal range around 25X over voltage. Some motors will actually
push the thermal limit at a much lower over voltage. I have one motor
that at about 10 - 15X over voltage will get roaring hot to the point
you can not touch it. Read the white paper, it is full of great
information and some really good graphs on this particular subject.

Tim
[Denver, CO]
Buy Sherline now before the Oct. 1 price increase!
Sherline & Taig products at Deep Discount
Mach1 & DeskCNC with credit card ordering
www.KTMarketing.com/Sherline
e-mail me at Timg @ KTMarketing.com for items not yet listed