[TowerTalk] stepping motors

[Jim Lux]

Steppers (particularly surplus ones) also tend to require a fair amount of
current (at least at the beginning of the step) at low voltages (designed to
run off 5V power supplies, for instance), and, if you want to run them fast,
require a modified waveform. That waveform may not be compatible with
hundreds of feet of control cable. I have used systems that had 200' of
multiconductor cable, but they were fancy Pacific Scientific higher voltage
motors and very expensive controllers.. certainly not 4 transistors and a
surplus 5V stepper from a printer or disk drive.

If I wanted to run a stepper at some distance away, I'd seriously consider
putting the controller with the motor and sending commands and raw power to
it.  There's a bunch of serial input (RS232,etc.) stepper controllers out
now at fairly low prices, and you could easily hook up an optoisolator on
the input.

----- Original Message -----
From: "Richard Karlquist" <richard at karlquist.com>
To: <k4oj at tampabay.rr.com>; "Tower Talk" <towertalk at contesting.com>
Sent: Thursday, January 15, 2004 6:16 AM
Subject: RE: [TowerTalk] stepping motors


>
> Stepping motors are great, except for one
> thing.  You need more wires to connect to
> the motor (at least 4 and sometimes 6).
> And in the 4 wire case, I don't believe
> any can be ground.  With a DC motor, you
> need 2 wires, which is really no wires if
> you use the center conductor and shield of
> the coax.
>
> In a remote application, running an extra
> control cable just to use a stepper may
> not be worth the effort.
>
> In non remote applications, I think steppers
> are the only way to go.
>
> Rick N6RK
>
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