Sunday, August 14, 2011

Power Supply for the steppers

I have chosen an old power supply from HP 32V 2.2A for the steppers since the NEMA17 is not over 0.7 and the NEMA23 will be limited to 1A. I have chosen to mount it temporarely via some washers in the channel and brackets.

Washers - wide 18mm(5mm internal)x1mm ( I will use them all over the place so get at least 50)

Bolts - any head 20mmx4mm will do ( again take at least 20 )

Brackets - 40mmx40mm right angle for wood frame

Held in place by zip ties.

You can get a dedicated power supply and depending on your motors choose a higher rated Amps.

Rule is generally add your stepper driver limit +5%~10%. No point in wasting money on more power than that.

In my case I will limit the Amps via the stepper drivers to collectively 2A and it will not be even at 25% duty cycle (calculating from 8sec exposure and 2sec tilting cycle).


  1. I liked your article is an interesting technology
    thanks to google I found you

  2. When using a switching power supply with stepper motors you should add a filter cap before the stepper motors, somewhere around 10000uf ought to be fine.

  3. Correct, but since we are talking a max draw of 1 A, 10000uf is overkill. Usually it is 200uf for every Amp of draw. If I have power problems I'll post and will use a 470uf capacitor.
    Thanks for the suggestion!