Stepper Driver Input Voltage - Filtering Required?

[RJS100]

My current control cabinet has three Stepper Online CL86Y stepper drivers that drive three Nema 34 steppers (X, Y & Z axis). These drivers and be driven with an ac or dc power source. I currently use a toroidal transformer to supply them 36/72V AC.

I am adding an additional driver to this control cabinet to drive a Nema 24 stepper. I planned on using a CL57t driver for this stepper. The CL57 accepts 36V DC. Does the power supply for stepper drivers need to be filtered or can I use a full wave rectifier alone (no capacitors/inductors) to convert the 36V ac to 36Vdc for this stepper driver?

The stepper only draws 4 amps. If filtering is required, would this do the trick:

https://www.amazon.com/gp/product/B0B9K ... CHVK0&th=1


Richard

[centroid467]

Peak voltage after the full wave bridge will be 36 Vrms * sqrt(2) so you'll end up with about 51 volts peak. You will need a bulk capacitance to clean up the resulting choppy waveform. Take a look here for a refresher: https://www.electronics-tutorials.ws/diode/diode_6.html. I think you'd be able to get away with a few volts of ripple for something like this so using that formula on the bottom of the linked page I think at least a 10mf will do the job.

The caps on that filter board are rated to 50V which is not great for a 50 V peak input. Electrolytic caps should be derated to about 70% for longevity. I think the board you linked is something that would go after the bulk filter cap to a load that cares about EMI rather than acting as the primary ripple reduction.

The CL57T is rated for 48 VDC input. I think you might need to do something like remove a turn from the 36V secondary to drop the voltage a little bit.

Here's a search on Digi-Key for suitable electrolytic caps: 10mF+, 70V rated minimum, not through hole mount so you don't have to solder to the leads

[RJS100]

Thanks for your thoughts. It has been 40+ years since I last looked at this stuff. It looks like for the cost of a capitor, I can grab a 36V switching power supply. Very much appreciate your thoughts.

Richard

[RJS100]

Just looked a bit closer. The output from the toroidal transfer is 35V, I can use a DM556 driver which is rated for a 50V input. If all I need is a full wave rectifier and a capacitor (No inductor). Do you think either of these would work:



https://www.amazon.com/6-8uF-100V-Capac ... hdGY&psc=1

https://www.amazon.com/Cermant-Capacito ... r=1-2&th=1


Richard

[centroid467]

I think you've gotten a few orders of magnitude off on the capacitance required. For less than 2V ripple, you need greater than 8 millifarads. Those are all microfarads. It'll be hard to find a suitable cap on Amazon.

You may remember when capacitors in the microfarad range were labelled with MFD. You'd be looking for a 10,000 MFD cap for this.
Something like these: https://www.amazon.com/10000uf-63v10000 ... 83&sr=1-19

[RJS100]

Thanks for all your effort. Really enjoyed the refresher course you provided!

Looks like I found a simple solution. A stepper driver that accepts ac or dc:

https://www.amazon.com/gp/product/B07G8 ... =UTF8&th=1

This should work perfectly to drive a Nema 24 stepper for my ATC.

Thanks again for your time.

Best... Richard

[suntravel]

If you want to use Genova and stepper,
will you use an extra pulse generator, or Acorns 4.th axis to drive the stepper?

Uwe

[RJS100]

Exactly. I will post the pulse generator, programming and schematic shortly.