[shreifali]

Dear all,
I have built the tachus42 driver board and it worked perfectly with small steppers.
I plan to use it on bigger steppers with different specifications. Two of the motors are identical and rated 3.4v and 2.84A. The third one is rated 4.2A but the voltage is not specified on the motor.
My question is can i use a 12v power supply independantly of the motors voltages? Or the power supply voltage must be less than the minimum motors voltage?
Thx in advance

[James Newton]

The stepper driver is responsible for regulating the voltage actually sent to the motors no matter what the supply voltage is. It needs a supply voltage higher than the motor max voltage in order to quickly change coil current flow between steps.

In short: Yes.

[shreifali]

Thx james for your reply,
Now another problem has arised
The steppers mentioned above are Nanotec 4H5618C0408 and they are eight wires black-balck/white-red-red/white-green-green/white-yellow-yellow/white.
I connected the black/white with the red/white and green/white to yellow/white, then i connected both of them to 12v power supply using the corresponding limit resistors.
Black and red are connected to tachus42 phase A pins (1,2) and green and yellow to phase B pins(1,2 to the right).
What happened is when i try to run the stepper it whines and doesn't turn. I tried playing with the speed nothing changed.i connected an ampermeter to one phase and the reading was 2.5A which i think is sufficient to make the stepper turn!
Any advice would be appreciated.
Thx in advance

[James Newton]

Check the motor wiring rather than relying on the colors. Documentation is often wrong.
Stepper Motor wiring