I'm in the process of looking for a power supply to power 5 stepper
motors for a robotics type application I am developing. The five
motors are size 17 bipolar hybrid stepping motors and I am powering
them with 5 microstepping drives. My specific questions involve
looking at the power requirements for my drives and motors and using
those figures to determine what I'm going to need in a power supply.

The drives are rated at 12-24 VDC, and have an adjustable max current of .25 to 1.4 Amp RMS/phase or .35 to 2.0 Amp/phase peak. The motors were tested at 1.4 Amp RMS at 12 volts and have plenty of torque at this range to satisfy my calculated requirements. I intend to start at 12 volts and hopefully this will be enough, but it would be nice to have a power supply that went up as high as 24 volts if I need to get more torque out of the motors than I expect.

The dives also require 5 volts at 7 mA for the logic circuits. According to the manufacturer if a separate 5 volt supply isn't provided it's acceptable to use a resister to drop the voltage. A separate computer power supply might also be a possibility to power the logic circuits of the drives.

My ideal solution would be to have one power supply to power all five drives. Something with an adjustable voltage or separate channels between 12 and 24 volts, or possibly even a separate 5 volt source for the logic circuits. I think my amperage requirement would then be 2 amp/phase x 2 phases/motor x 5 motors = 20 Amps. This is assuming I need to use the peak amp figure and not the RMS figure. I think this would then give me a power requirement of 12 volts x 20 Amps = 240 Watts (using 12 volts) up 480 Watts (using 24 volts). But maybe it is not the most economical, practical, or even possible to use the same power source for all five motors.

So, my questions are:

Did I calculate the correct specifications for power requirements for a power source?

Does anyone know good places to look for the power source described? The more economical the better.

Would I be better off with 5 smaller power supplies rather than one big one, and if so where can I find those?

Also, am I correct in this assumption: A 20 Amp power supply, supplies UP TO 20 Amps, but only when 20 Amps are being drawn. I need a 20 Amp supply to hook up 5 – 2 Amp/phase motors with 2 phases each, but in situations where I just want to move one motor at a time then only a maximum of 4 amps will be used for that time and the power supply will only put out 4 amps. Is that correct?

This isn't exactly my area of expertise and any help would be greatly appreciated.

Thanks, Jason

The drives are rated at 12-24 VDC, and have an adjustable max current of .25 to 1.4 Amp RMS/phase or .35 to 2.0 Amp/phase peak. The motors were tested at 1.4 Amp RMS at 12 volts and have plenty of torque at this range to satisfy my calculated requirements. I intend to start at 12 volts and hopefully this will be enough, but it would be nice to have a power supply that went up as high as 24 volts if I need to get more torque out of the motors than I expect.

The dives also require 5 volts at 7 mA for the logic circuits. According to the manufacturer if a separate 5 volt supply isn't provided it's acceptable to use a resister to drop the voltage. A separate computer power supply might also be a possibility to power the logic circuits of the drives.

My ideal solution would be to have one power supply to power all five drives. Something with an adjustable voltage or separate channels between 12 and 24 volts, or possibly even a separate 5 volt source for the logic circuits. I think my amperage requirement would then be 2 amp/phase x 2 phases/motor x 5 motors = 20 Amps. This is assuming I need to use the peak amp figure and not the RMS figure. I think this would then give me a power requirement of 12 volts x 20 Amps = 240 Watts (using 12 volts) up 480 Watts (using 24 volts). But maybe it is not the most economical, practical, or even possible to use the same power source for all five motors.

So, my questions are:

Did I calculate the correct specifications for power requirements for a power source?

Does anyone know good places to look for the power source described? The more economical the better.

Would I be better off with 5 smaller power supplies rather than one big one, and if so where can I find those?

Also, am I correct in this assumption: A 20 Amp power supply, supplies UP TO 20 Amps, but only when 20 Amps are being drawn. I need a 20 Amp supply to hook up 5 – 2 Amp/phase motors with 2 phases each, but in situations where I just want to move one motor at a time then only a maximum of 4 amps will be used for that time and the power supply will only put out 4 amps. Is that correct?

This isn't exactly my area of expertise and any help would be greatly appreciated.

Thanks, Jason