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burnley1
Someone on the forum told me about inductance, that I should have around 90-100 volts of voltage from powersupply for 6.8 mH of inductance.... what do you think?
Let's do some sums. The current in one winding goes from maximum positive, through zero to maximum negative, and back to maximum positive every 4 full steps. So if you run the motor at its full rated current of 3A, the controller has the time for 2 full steps to change the current from +3A to -3A. You are looking for 1500rpm, which is 25rps, so there will be 25 * 200 = 5000 full steps per second, which is one full step every 200us. Therefore in 400us the driver needs to achieve a change in current of 6A. The voltage needed to achieve this is V = L*I/t = 6.8mH * 6A / 400us = 102V. And that doesn't take account of the additional back emf generated by the rotation.
So that person was right. If you don't need the full torque, then you could run the stepper motor at lower current and you wouldn't need so much voltage. But even at half rated current, you would need at least 51V, and the PSU in that package is only 24V. Being realistic, even 500rpm will be difficult to achieve.
A stepper motor is not a good choice for these speeds. A DC motor (brushed or brushless) would be more suitable.