Re: [CAD_CAM_EDM_DRO] Servo motor voltage

Chris Baugher wrote:

>Hi,
>I notice in the manual for the Gecko G320 it says not to go more than
>5 volts over the rated voltage for servos. What I'm wondering is, why 5
>volts? I'm building a supply for 60V motors and I found some 48V
>transformers for fairly cheap. This would get me:
>
>(48V * 1.4142) - 1.4V = 66.5V
>
>Would this be too much for 60V motors? Should I add some diodes to drop
>the voltage a bit?
>
>

Not needed. And, there are conditions where energy can be returned to
the power
source, so you want the other drives and the big cap to be able to
absorb that.

A 60 V motor will not be harmed at all by running on 66.5 V. The
voltage rating
of a DC brush motor is really a VERY vague number, with a couple of
exceptions.
In cases where there is no current limiting, applying full bus voltage
to a stopped
motor can result in huge currents that can ruin the motor (by
demagnetizing the
permanent magnets, for instance.) A servo drive will not run the motor
at full
supply voltage except under rare conditions, such as hard acceleration
while already
at full speed. Current in permanent magnet motors must be carefully watched
to prevent harming the magnets. But, any servo drive should do that.

Jon