Orac Stepper Motor Current Limit

XJ5373 · Post by **XJ5373** » Thu 13 Nov , 2008 13:32 pm

Hi,
Just finishing off a conversion putting Mach3 onto an old Orac using Gecko drives and a CNC4PC breakout board.
What should the current limit be set to for the X and Z stepper motor drives? I see that the original electronics had 7.5A fuses in the lines between the torroidal transformer and the bridge rectifier but this seems rather high??

Thanks

Ian

Andycnc · Post by **Andycnc** » Sun 23 Nov , 2008 16:37 pm

Your original drives (CD20) would be 3amp. You may get a bit more cutting force and acheive higher feed rates with higher currents but this puts extra stress on the machine.

I'd keep to sensible traverse rates of perhaps 1000mm/min max I wouldn't go much above 4 amps drive.

My best guess would be that the fuses were over-rated to cope with short term transients (which can also occur at power-on).

XJ5373 · Post by **XJ5373** » Sun 23 Nov , 2008 19:00 pm

Thanks vey much for this reply - 4 Amps it is then.

Now to get the tool changer working....

Ian

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