Stepper motor Driver Compatibility

Hey guys

I'm looking at these stepper motors and drivers I just want to make sure they are compatible. The thing I'm most concerned about is the current of the stepper. The stepper is rated at 2.8A and the drivers are rated a 2A per coil. So in theory the driver is rated for 4A?

Thanks

Ian

Stepper Driver

Stepper motor

Those drivers will work with those motors, but don't believe the advertising. You won't get 2 amps/coil out of the A4988, but you can count on 1 amp and perhaps 1.5 amps with forced air cooling.

The stepper current rating is just the maximum steady state current allowable; higher than that the motor overheats.

The A4988 driver boards in principle allow you to set the current limit to something the driver will tolerate, which means the maximum torque will be less than the advertised value at maximum current. The product page for the Pololu A4988 driver has a lot of useful information.

If you need the full 2.8 amps per coil to get full torque from your motor you will need much more powerful (and expensive) drivers. Google for a 3 or 4 amp stepper driver - or try Ebay.

If your project does not need the full motor torque it would make sense to buy a motor that operates within the limits of the A4988. The Pololu DRV8825 drivers can manage a little more current than the A4988.

Have a look at stepper motor basics

...R

jremington:
The stepper current rating is just the maximum steady state current allowable; higher than that the motor overheats.

which means that instead of frying an egg on the motor in a minute, an overheated motor might fry the egg in 20 seconds. either way, a acceptable temperature is well beyond your hand resting on the motor.

Hey guys

I know have the motors and DRV8825 for the drivers

The rated current is 2.8A is that per phase or the whole motor. I have the current limit set at 2.8A (or Vref 1.4V). Is this correct because I am getting very stuttery output of the motor (even at low speeds)

Thanks
Ian

I wonder how (and why) you have the current limit set at 2.8 amps on a 2.2 amp driver board?
Also, to get the full 2.2 amps you will need a heat sink and maybe a cooling fan.

I presume you have read the Pololu DRV8825 webpage carefully.

The 2.8 amp rating normally means per coil.

Try setting the current limit for 1.5 amps (which should not need a heat sink) and see what happens.

If you want to get the full torque from that motor you will need a more powerful driver board.

Finally, what power supply (volts and amps) are you using for the motor?

...R