EasyDriver unstable at 24v

[ehud42]

I have been slowly building a CNC router over the past year. Currently my Z-Axis is driven by a 12V 30ohm 48 step / rotation stepper via the EasyDriver from SparkFun.

It works, but is slow. I'm powering it with the 12V from a computer power supply.

To speed it up, I bought a 24V switching power supply, however, the driver becomes erratic and seems to loose steps.

I replaced the motor with a much bigger motor 3V 2A (which the EasyStepper cannot fully drive as it is only 750mA), and running on 12V it is much faster than the smaller motor. But again, when I connect the 24V power supply to the EasyDriver, it becomes erratic and looses steps - and it seems to have more problems in one direction than another.

Any suggestions?

[H500]

Did you try a linear supply? Some switching supplies does not work with motor drivers. Try putting a 1000 uF 50v capacitor across the power supply.

[James Newton]

If you have a multimeter, measure the output of the power supply under load using the AC setting on the meter. There shouldn't be more than a volt of AC component in the power supply output. If there is, H500 is right on with the capacitor. Umm... be careful. Big caps can explode if you get them on wrong way round and they can kill you dead if you touch the leads after they are charged and disconnected.

If that isn't it, then you may be getting midband resonance. The easy driver is pretty bad for that since it's a simple chopper. You might try adding a mechanical resonance damper. The Hockey Puck design is said to work well.