RE: [CAD_CAM_EDM_DRO] simple stepper power question.

When I first got started in cnc and step motor driver kits,I looked at
ways to measure the torque of various motors and the performance of
various drivers at various output voltage. I heard of using a weight
with a pulley on the motor and figured that was too crude.
So I designed my own and machined a flanged pulley for the stepper motor
to a radius of .967 and that added to one half of the thickness of my
nylon cord equaled 1.00" radius so my readings would be in oz inches. I
made a motor mount and then using a deadhead on one side I attached a
spring scale. With the motor running at the speed I wanted, it(the
pulley)performs like a capstan. When the cord is slack, it slips and no
torque is noted. As I pull (I have a spring scale on this side to
measure this pull also)on the other end of the cord that is wrapped
several times around the pulley which has a spring scale, I note the
reading on the spring scale. I set up a matrix and recorded the torque
and the current for each speed I wanted to measure. There's a bit more
to it but is much more controllable than other methods and it got the
measurements that I wanted.
Dan

-----Original Message-----
From: dave_ace_me [mailto:davemucha@...]
Sent: Thursday, April 18, 2002 5:07 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] simple stepper power question.

is there a formula to determine power of a stepper ?

I have a Slo-Syn NEMA 34, 1.7 volt, 4.5 amp
single stack.


Also, has anyone put together a simple test
for stepper power ? Seems like a weight,
and a long crank arm with holes drilled
each inch would allow one to keep moving
the wieght farther out until the motor
started missing steps.

Dave





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