Quote Originally Posted by Clive S View Post
I think you will find that all the outputs are connected together so you can just connect two to one of the outputs.
If you read the Gecko manual it says that the motor voltage can be up to 20 time the rated voltage on the motor ie. 75.6V
The 20 times motor voltage is a very rough guide for maximum voltage. If the motor inductance is known, the sqrt of the inductance times 32 is a more accurate voltage.

Gecko cover it in the power supply section of their stepper motor basics guide - http://www.geckodrive.com/support.html