Test your stepper motor before you connect it to SP1

1. Check resistance of windings - they should be less than 20 Ohm. Less the resistance, less the heat will be dissipated in motor while motion or standby (hold) mode. The dissipated heat power (do not confuse it with power which does a job) is calculated according to formula:
P = I*I*R,
where I is the current applied to Stepper motor winding, R - the resistance of windings. Standby power is Pst = 0.4 * P,
For example:
I = 0.8 A, R = 20 Ohm gives 12.8W power while motion is enabled, and 5.12W power in standby mode. The dissipated heat is too high for the most motors. Stepper motor with R = 6 Ohm dissipates 3 times less heat for the same windings current.

2. Test your stepper motor. Turn Stepper motor rotor clockwise or reverse by hand. Can you feel steps while rotor is in motion? If not, that means that Stepper motor steps are not well defined. It probably will make you problems with precise positioning in most cases, especially if heavy load is used.

Note: Toshiba TA8435H stepper motor driver output directly "comes" to Stepper motor. The driver specifications may be found on the web. SP1 electronic circuit is available for RST customers on CD, attached to SP1 controller.