Driving a stepper motor at higher voltages

[eljainc]

Hello,

I have some low end stepper motors, made by Howard Industries, part
number 1-19-4203. They are bipolar stepper motors (2 phases, 4 leads).
The Inductunce is 31mH, and the phase resistance is 25 Ohms. I am not
sure (can't find the spec for) of the current per phase. I would
like to run this motor at a higher voltage. Does anyone know what the
maximum voltage might be? I know it does depend on the current
ratings. I tentatively have a 1A power supply at 48V. I would not be
running this motor for long periods of time (short duty cycle). Would
this be a safe undertaking or is there a way to find the max voltage
of this motor? I googled and could not find any other specs on this
motor.

Thanks
Mike

 

[mike]

Higher voltage than what? Without knowing what they're rated for, your
"higher" voltage may be a "lower" one.

Fancy stepper drives control the current through the motor, to insure
torque at high speeds even when the motor is generating back EMF.

If I had to use an unrated motor like that, I'd experiment to find the
current I could drive through it without making it too hot after it had
been sitting there at full current for an hour. I'd aim for about a
50-70 degree C rise above ambient at the motor case, and no nasty
smells, smoke, or melted bits.

Remember that power = I^2 R, so each 2x step in current is a 4x step in
power.

Stepper motors run on CURRENT. Ohm's law defines the steady state
relationahip
between current/volts/ohms/power dissipated in the winding.
Depending on your application, you may be more interested in the inductance.
When you apply volts, it takes time to ramp (exponential) up the
current. It's not unusual to use higher voltage with a current limit
to get speed.

Depending on your application, you may have more questions than you
are currently aware of...inductor saturation may impose further limits.