From: Kevin McMurtrie
Subject: Re: 3 wire stepper motors
User-Agent: MT-NewsWatcher/3.2 (PPC Mac OS X)
Date: Thu, 26 Sep 2002 21:18:11 GMT
NNTP-Posting-Date: Thu, 26 Sep 2002 14:18:11 PDT
In article <email@example.com>,
firstname.lastname@example.org (Ralph Seguin) wrote:
>I noticed at a surplus shop some Superior Electric NEMA 34 stepper
>motors, 120V, 0.3A, 50 oz-in, 3 wire.
>What is a 3 wire stepper motor?
>How does one drive them?
>I have a really small budget ($0 if you ask my wife :-), so I don't
>think I can afford all the nice servo and stepper stuff.
>I have a 3 axis stage with 10 TPI Acme screws on X and Y and a
>ballscrew on Z that I'd like to make into a little mini-CNC mill.
>I know that 50 oz-in is pretty low compared to some of the 150-250
>oz-in motors that I've seen, but those other motors are pricey.
>I was thinking of rectifying 120V AC to 120V DC and using that as a
>power source, or maybe rectifying 240V AC to DC. Is this a bad idea?
>Are these motors worth investigating, or should I save my pennies?
>Inexpensive source for kick ass motors, drives, controllers, ...? :-)
>Inexpensive source for power FETs?
>Inexpensive source for rectifiers?
>Inexpensive source for power diodes?
>rpseguin AT yahoo DOT com
They're meant to be driven off 50-60 Hz AC using a capacitor to phase
shift one of the two coils. They'd probably be a major pain to drive
from electronics since you'd need 40 to 80 VDC, maybe even 100+ VDC with
a parallel R and C in series with the motor to limit the holding current.
Have you looked at discarded flatbed scanners and old hard drives?