If they have 6 wires, then they are designed for unipolar drive, and the 11 amps is probably the unipolar rating. If you drive them bipolar using the outside wires and leaving the center taps unconnected, you will get the same torque using half the current. Driving them bipolar using all the coils like that, you can usually run them at .707 times the unipolar current and get increased torque. |