RE: [CAD_CAM_EDM_DRO] Problem with overhauled steppers

I have had a little experience with demagnitized NEMA 42 steppers. Had
one on Bridgett when I got her. The most obvious symptom was that when I
turned the motor by hand there was very little cogging on the bad motor.
NEMA 42 motors have pretty stiff detent torque (cogging) and you can
really feel them snap into place. The bad motor felt about like a little
50 in/oz NEMA 23. Without a known good motor it is hard to give you much
to go on other than to try turning it bare shaft by hand and if it spins
easy they are probably dead. I actually would not feel to bad about it
as a 12 V 1.7 amp stepper on a 37 v supply will be pretty doggy once you
beyond very slow speeds.

Tim
[Denver, CO]
Sherline products at Deep Discount
Mach1 & DeskCNC with credit card ordering
www.KTMarketing.com/Sherline

> -----Original Message-----
> I'm having a problem with a stepper that I overhauled, heres
> the setup. I have 4 of Dan's 5 Amp stepper boards yes I've had them
> for a while, they are working fine I think! I have a 37v
> 10amp supply running the whole thing software is Desknc. I
> bought 3 Sigma Inst. unipolar steppers way before this
> list was around to get advice. They are or were 5 wire
> motors I took them
> apart and brought out all 8 leads. About 2 weeks later the
> list discussed not doing this without an iron core to avoid
> demagnetizing the motors too late for me I was done by then.
> Here is the problem no matter how I configure them in desknc
> when I jog them from desknc or by running a small test
> program the motor just won't make a
> complete step. The motors are size 42's rated at 12v 1.7a
> unipolar I'm
> running them wired half-winding at 1.7a. The motor is on the
> X axis of a
> shoptask 3 in 1 mill. Any advice? Is this caused by we
> overhauling these?
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html