Re: [CAD_CAM_EDM_DRO] Sizing a power supply

"Carey L. Culpepper" wrote:

>

..... Just for grins I decided to hook my digital meter in

> series with the power supply to the driver.I am running the six wire
> motors in series with the center wire unused. While running, the
> motor/driver drew about3.8A. But when holding(not turning) it drew 10A.

no good using a digial meter here. The current is a chopped current, not
a steady DC. What the meter will show is a kind of average value, but
not one of any use- think about the current going on and off- at the
chopper rate while the motor is at rest, then further switched by the
step pulses while its moving. The digital meter keeps sampling the
current, at a completely different frequency determined by the meter,
sometimes it reads when the current is high, sometimes low. but in any
case the reading is useless.

The only way to measure the current is to use a scope, then you have to
do an integration to get the average current since the current is
chopped. Not easy.

ron