Freshly fried stepper...mmm

Hello,

I thought I would make life interesting by plugging in a stepper while the 5A supply was live on my ramps board. Now it just judders around a bit, but doesn't turn.

I've checked the resistance across the 2 pairs of wires. While before both pairs had around 3.5 Ohms, now the red/blue pair is open circuit.

I have tried that stepper on a different driver, same outcome, and I've tried a different stepper on the driver that was plugged into live, and it seems fine. I also tried trimming the reference voltage on the pololu a bit higher in case that helped, but no joy.

I've just ordererd another Nema17 from ebay, it was only 12 quid. Is the micro-stepping support just in the pololu driver only, or does the motor have to support it too? The model I bought was numbered: 17HS19-1684S NEMA 17

Thanks,

James

Sorry to hear about your fried motor, microstepping is a function of the driver rather than the motor. It's done by the driver supplying the windings with intermediate levels of current inbetween fully on and off to produce a movement less than a full step.

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Prussa i2 Comissioned 4-Nov-2013
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Many thanks for the info.