Re: Stepper Voltage and Current question

I plan on limiting the current through transistors not resistors.
This way when I pull 25 volts or 50 volts it will be limited to 2
amps to the motor. I may also use FET's to keep the heat down. I just
need to know if each winding is rated for 2 amps or is it divided
between the 4. I was just curious performance wise how much voltage I
needed. I may add a chopper cicuit by adding a 555 timer to the
tranistor circuit but am working on the basic circuit first and try
to make sure what I need voltage and current wise.

Gecko drives are nice but at $130 a piece I figure I can design my
own a lot cheaper since this will be my first table and can always
upgrade if the need be.

Thanks

--- In CAD_CAM_EDM_DRO@y..., "Bob Stone" <spoothammer@h...> wrote:
> Hi,
>
> If the motors are 3 volts and 2 amps, that means the windings are
1.5 ohms.
> If you apply 25 volts to these coils you'll draw almost 17 amps
which will
> shut down your supply, toast your driver circuit, etc.
>
> To limit current, say at 25 volts, you'd need a approx. an 11 ohm
power
> resistor that could handle 110 watts. That would be nuts. You
better have a
> chopper drive and even then I'd go to a higher voltage motor with
that
> supply.
>
> bob
>
> >From: "starcast82" <rh@g...>
> >Reply-To: CAD_CAM_EDM_DRO@y...
> >To: CAD_CAM_EDM_DRO@y...
> >Subject: [CAD_CAM_EDM_DRO] Stepper Voltage and Current question
> >Date: Fri, 03 May 2002 05:10:07 -0000
> >
> >I am currently starting to design my stepper drive and wanted to
make
> >sure of a couple things. I hate to see smoke. First off I have 3
> >volt, 2 amp unipolar stepper motors.
> >
> >1. I plan on using 25 volt supply, is this enough or should I jump
up
> >to 50 volts ? I read I can go 20 times the rated voltage.
> >
> >2. As far as current limiting goes, since I have 2 amp motors, from
> >what little I found from reading, does this mean I can run 2 amps
> >through each of the 4 coils <what I read> or does this mean I can
> >run .5 amp through each coil ?
> >
> >Thanks for the help
> >If anyone is interested in what I come up with when I'm finished
I'll
> >be more than happy to post it.
> >
> >
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