Hey, so I am building a CNC machine and I bought : LINK as the electronics for it, it came with two power supplies rated at 9.7A, 36V each. The machine will use more than 9.7A total, so how do I wire up the two power supplies to get 36V but ~19.4A?

I initially thought that putting them in parallel would be fine but I get the feeling it is not...

I have 4 nema 23 steppers and stepper drivers, should I just use the power supplies to power two drivers each? How would I wire this up, just tie all of the grounds together or is there a better way?

I have no formal electronics training (self taught) so sorry if my questions seem like stupid ideas.

 

Just put them in parallel ,the problem will be if one psu gives out more than the other they won't be balanced.

 

You should be able to connect two of the driver modules to each power supply.

Incidentally, where does the 5V for the breakout board come from?

[Edited to make sense ]

 

You should be able to to two of the driver modules to each power supply.

Incidentally, where does the 5V for the breakout board come from?

I'm gonna use a dc-dc converter to make 5V for the control electronics

 

Also, if I power two of the steppers per power supply, should I connect all of the grounds together to every stepper, and then just put the +36V to the power in on each one?

or should I not connect all grounds together if i am powering the steppers 2 and 2

 

Don't connect the 36V grounds together.
The inputs to the driver modules are opto-isolated so no grounds needed there.

 

What stepper drivers are you using? the P.S. +&- are going to be made common when you feed both drives.
Or by 'Ground' do you mean Earth ground or just power common?
Realistically a SMPS/regulated supply is not needed for steppers and are generally a bad idea, they are not as rugged as a linear supply and have a higher failure rate due to the BEMF etc of stepper motors.
Also if you were to use a Toroidal transformer supply, it is very simple to put a small winding on for the 5v supply.
Max.

 

Don't connect the 36V grounds together.
The inputs to the driver modules are opto-isolated so no grounds needed there.

So basically I should have: 1 power supply connected to 2 stepper drivers, ground not connected between power supplies or pairs of stepper drivers.
Then for the control electronics (arduino + the optoisolator board in the ebay link), can I just hook up a DC-DC buck converter from one of the 36V supplies (input) and have 5V output to power control electronics? or will this potentially send power that s problematic due to BEMF and other issues from steppers. Would it be much better to use a separate power supply (a 5V one) to power arduino etc.

 

The buck converter should be fine.

 

The buck converter should be fine.

Awesome thanks, was starting to feel like this was way more complicated then I could manage as other threads were on about different diodes and stuff, gonna do it this way with the buck converter connected to the motors that will do the least on the machine (to be sure I don't draw too much power on the power supply).