Re: [CAD_CAM_EDM_DRO] Minimum inductance for G320 motors and how to measure it.

Kim Lux wrote:

>Does anyone know what the minimum acceptable motor inductance is for a
>G320 ?
>

I don't think it is on the downloadable pdf files on the gecko web site.
The actual value depends on applied voltage, too. You will get a
triangle-wave current through the motor when the drive is idling,
due to the 50% duty cycle square wave applied by the drive. As long
as this current is not excessive, and it doesn't cause excessive iron
losses in the motor (depends on a lot more than just inductance)
then it is not a problem. But, you can figure the peak current will be
E * 10 uS/L, and the peak-peak ripple will be twice that. Units are
E, in DC Volts and L in Henries, the result in Amps. So, for 60 V
and a 100 uH motor, you'd get a peak current of 6 A. That would likely
cause some serious motor heating.

>
>How does one measure this inductance ? Can one put an inductance meter
>across the motor terminals and measure it that way ?
>

Yes, sure.

>
>Should I find the inductance of my motor too low, can I add inductance
>externally to compensate ?
>
>

Yes, that should work. You'd want a moderately lossy inductor that can
tolerate lots of delta I.

Jon