PICStep & HobbyCNC motors?

[Lionclaw]

I'm definitely a noob when it comes to this stuff.

My current machine uses a hobbycnc controller with the 200oz motors Dave sells. I'd like to make PICStep controllers for my next machine, and I'd like to use them with the 200oz motors from hobbycnc.

I know the PICStep controller is made for bipolar motors, and the hobbycnc board is unipolar. But, an auction on ebay led me to believe I can use 4 of the 6 wires from the motors and run the motor in bipolar mode. Can anyone confirm this? Will I get more/less torque from the motors if they were run in bipolar mode?

[pminmo]

You can use 6 wire motors bipolar. You should gain about 25% in power with the same motor running bipolar over running it unipolar.

[BCwanderer]

6 wire steppers are often unipolar motors.
They have two windings on each pole.
Each winding is phased opposite to the other.

To run a unipolar motor in bipolar mode you use one of the coils on each phase. The second coil is abandoned

If you put an ohm meter across the coils, you often find the power lead is the center of two coils. These coils are wrapped opposite on the pole.

If you open the back of the motor, you can sometimes access the wiring.

Find the center tap and separate the wires to each coil. Leave the original power wire on one coil and cut apart the wire feeding the second coil on the pole. Add a wire to the second coil and bring it out to your wiring harness.

Do this for both poles and you will have an 8 wire motor instead of a 6 wire motor.

You must then phase the coils on each pole to add field and not buck each other. You can do this by wiring the original power wire as power and the added wire as ground. If you wire them in parrallel, the current draw will increase. If you wire the coils in series, the current will stay the same but the voltage will double.
Torque will increase substantually.

I have done this successfully on Slo/Syn motors. The wiring is very easily accessable.
I'm not sure how your motor opens.