RE: [CAD_CAM_EDM_DRO] Stepper motors and increased Amps

Sounds like we know enough to generalize now. The motors are unipolar and
the rating is likely the unipolar rating. You have them hooked up as bipolar
series (your other choice is bipolar 1/2 winding). The way you have them
will give the maximum low speed torque, but the high speed torque will
suffer. If you go to 1/2 windings you will get better high speed torque due
to the reduced inductance, but the low speed torque will degrade slightly.

Wired the way you have them you should be driving them at a maximum of .6
amps. A safer level that would give almost the same torque would be about .4
amps. If you go to 1/2 coil you do use a higher current. I don't remember
the figures based off of the unipolar rating, but I am going to guess that
it is the 1 amp unipolar rating and then back off a little for some leeway.

Increasing the current will only increase the low speed torque a little and
that is at the risk of burning the poor things up.

Tim
[Denver, CO]

>
> Tim,
>
> The motors have 6 wires, red, red/white, black, green, green/white and
> white. Black and white are the common between 4 coils according to the
> document supplied with the motors. Black and White are not used
> currently.
>
> I am basically curious as to whether increased current increases
> the torque
> provided by the motor. These are rated at 59.7 oz/in holding
> torque and 34.7
> oz/in pull torque.
>
> John
>