Confused about stepper sizing

**Jeff** · 22-09-2017

Thanks guys, really great insights.

I guess that the lazy ass part of me thought that 48v was good because I could get away with an off the shelf PSU instead of building a 70v 12A linear :)

**Clive S** · 22-09-2017

Originally Posted by Jeff

Thanks guys, really great insights.

I guess that the lazy ass part of me thought that 48v was good because I could get away with an off the shelf PSU instead of building a 70v 12A linear :)

Jeff here is the stock answer

https://www.rapidonline.com/50a-brid...al-case-519318

https://www.rapidonline.com/samwha-h...acitor-11-3121

https://www.rapidonline.com/lcr-ep08...-clamp-11-3004

https://www.rapidonline.com/single-primary?attributes={%22Secondary%20Voltage%22:[%222%20x%2024V%22],%22Power%22:[%22500VA%22]}

the above is 500va but 625Va will give you a bit more upth.

**Jeff** · 22-09-2017

Thanks Clive, ordered the 25v-25v 625Va... Bigger is always better :)

**Clive S** · 22-09-2017

Originally Posted by Jeff

Thanks Clive, ordered the 25v-25v 625Va... Bigger is always better :)

I take it you ordered three caps

**Jeff** · 22-09-2017

yeah, I realised it would be 3 x 4700uF in parallel, thanks again.

**Desertboy** · 23-09-2017

"Selecting Supply Voltage

The power MOSFETS inside the AM882 can actually operate within +20 ~ +80VDC, including
power input fluctuation and back EMF voltage generated by motor coils during motor shaft
deceleration. Higher supply voltage can increase motor torque at higher speeds, thus helpful for
avoiding losing steps. However, higher voltage may cause bigger motor vibration at lower speed, and
it may also cause over-voltage protection or even drive damage. Therefore, it is suggested to choose
only sufficiently high supply voltage for intended applications, and it is suggested to use power
supplies with theoretical output voltage of +20 ~ +72VDC, leaving room for power fluctuation and
back-EMF."

from the AM882 manual obviously check your stepper driver specs first.

Personally I went with 68v on advice from the forums the PSU build was very easy with Clive S help and I spent longer worrying about it than it took to build which was about 2 hours with 1 hour of pottering, smoking cig and drinking tea.

Good luck with your build ;)