Power supply ???

[rpe]

Hi, I have the hobbycnc pro 4 axis board and 4 of these step motors http://www.kelinginc.net/KL23H286-20-8B.pdf. I was wondering what power supply I would need for this combo. I was thinking 24 or 36 volt but the amps is were I'm getting confused.

[KOC62]

You will get different answers depending who answers. The motor currents are dynamic and constantly changing. If all your motors are ON then the sum of the average motor currents is what is drawn from the power supply.

The motor currents are different for different connections like SERIES, BIPOLAR, UNIPOLAR. The bipolar connection uses the most current, 2.8A in your case.

You could start with the sum of the average motor currents and then take 75% of that as your power supply current. It is unlikely that all motors are on full bore at the same time for an extended period of time.

[rpe]

Thanks for your reply. So if I'm understanding what you are saying a 15 amp power supply would handle the steppers if all would be on at the same time.

[KOC62]

Yes, 15amps would be more than adequate.

I was looking at the bipolar connection, 2.8A X 4 steppers X 75% = 8.4amps for most of the time. Some people like the comfort of using 100% availability and end up with a 12amp supply. Its all about estimating the probability of the motors all being on at the same time under full load. That's what the "75%" factor is trying to do.

[rpe]

Cool thanks for your help.