Is this a good AC snubber for a stepper motor? And would a driver integrate a snubber of some sort?

Thread Starter

-live wire-

Joined Dec 22, 2017
959
I will be doing some robotics stuff with stepper motors soon. I will be getting a 24V 20A power supply (to not overload it), some 2A stepper motors, and these motor drivers. I am concerned that with larger currents, the inductive spiking of the stepper motors may damage the drivers. Is it standard for drivers to integrate snubbers?

If not, is this PMOS snubber a good design?
upload_2018-8-4_10-46-34.png
The signals are 5V signals from a microcontroller that control the step it's on (so it would be parralel to the driver). V+ and ground refers to that of the μC. This is supposed to turn both PMOS on if there is no signal to apply + or - to the coil. I could also add a low value resistor in series with the coil, but I am trying to minimize the required components.
 

crutschow

Joined Mar 14, 2008
34,671
The circuit has no ground connection for the motor circuit, so it cannot work.
Tell us exactly what you want the motor to do for all combinations of input signal.
I expect you likely need a bridge circuit to do what you want.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
959
Sorry if I wasn’t clear. This is only the snubber part of it. The coil is one of the stepper motor coils. It is driven by a separate 24V 20A power supply. There is a CC driver for each coil with an H-bridge in it. The signals go also to the driver.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
959
It’s not like they’d make the driver out of BJTs or something, so I guess I’m good. Given how sensitive MOSFETs can be to overvoltages, I wanted to make sure there would be something to clamp the voltage. I didn’t realize they could do it. :eek:Also, “mosfets” autocorrected to “midgets”. I almost didn’t notice. I’m typing this on my phone because my computer is getting repaired (broken screen).:(
 
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