G320 and back-EMF from servo

[rc-cellar]

I have a router with G320's/ Clifton servos. When I move an axis manually (push with my hand or use handwheel), the servo turns and generates a voltage back to the G320. With power off, it is enough to make the fault LED come on momentarily (brightness varies with speed).

Is this OK with the Gecko? hopefully it's harmlessly drained away.
How about with power-on and in fault mode?

Thanks for any input...

[ViperTX]

It should be okay....generally the MOSFETs have flyback or back EMF diodes from drain to source....so, your servos are acting like generators and feeding voltage back into the capacitor of your power supply.....the Geckos see the power and....well I won't get further into the details...cause I see a design optimization.....

[ESjaavik]

I would not expect that to be designed in, the effects might be quite unpredictable.
Why don't you either disconnect the drives, or do manual running using the jog or
a pulse/direction generator? Jogging will have the advantage of seeing the position
information on screen.

[HomeCNC]

This is a known effect. Mariss of Geckodrive has explained this somewhere on a paper. Ask Mariss on the design of the servo box and how to protect your system. I think it has something to do with a capasitor and the size of it needs to be able to take the charging load when the servo motors back feed power.

[Mariss Freimanis]

No protection is necessary because it does no harm. Not unless you have Popeye's arms and can backdrive it past the 80V limit of the drive. Before that happens, the voltage would get high enough (>18VDC) to wake-up the drive which would then have the motor fighting you with every in-oz of its torque.

Mariss

[rc-cellar]

Thank you Mariss... I will not 'eats me spinach' while in the shop.