Re: Stepper Power Supply

Please remember that a transformer is commonly rated for continuous use, normally on a resistive load. That completely changes
the rating once you have a capacitive input rectifier. After the capacitor, you can talk about DC current and DC voltage
ratings.

Your typical servos or stepper motors will only draw peak currents during full torque accelerations. Once they are up to speed,
the current will drop quickly.

What this boils down to in practice is:
If the transformer runs at reasonable temperature when used to run your CNC, it is fine from power over load consideration.

A "weak" transformer might drop the output voltage too much under temporary peak load and be unacceptable because of the reason.

Hopefully this will add some practical "feel" for the problem.

Bertho Boman
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> From: John Ross <johnr@...>
>
> I'm using oriental motors vexta ph299 series.
>
> specs from the oriental motor 1997 catalog...
> <snip>
> holding torque - 375 oz-in unipolar
> current per phase - 4 amps unipolar, 2.82 amps bipolar
> voltage per phase - 3 volts unipolar, 4.25 volts bipolar
> winding specs. - 0.75 ohm/winding and 4.5 mh/winding
> <snip>
>
> John R.