Re: determining stepper motor current

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mariss Freimanis"
<mariss92705@y...> wrote:

>
> Actually a battery powered multimeter set to DC Amps at very
> low speeds (< 1 step per sec) or AC Amps at higher speeds
> (>240 full steps per sec) is a terrific and very accurate way
> to measure step motor phase current directly. Mind that the
> current will be Amps RMS for the AC setting.

Mariss:

How much PWM ripple current is there with a G201? I'm used
to working with VFDs, where the PWM is lower (4KHz) and the
motor inductance is also lower - I don't trust a DMM in such
cases, since ripple current can be 10-20% of the total current.

As an aside, if using a DMM to measure motor current, make
sure the connections are solid. Connect and disconnect the
meter with the drive powered off. Opening a motor lead
while running can toast the drive.

John Kasunich