Re: [CAD_CAM_EDM_DRO] Worry, servo back powering Gecko

Roger Swift wrote:

> When I manually position my servo mill (Tree Journeyman 350) with power off
> the servos generate enough power to light up the Gecko 340's fault lights.
> The table servos are large (rated 20 amps @ 90 volts) and connected through
> a 3:1 reduction. The mill has both hand wheels and servos.
>
> Do I need to worry about frying the Gecko's? Do I need to put in a relay
> between the Gecko and motor or remove the hand wheels?

Obviously, Mariss can answer this better than I can, but this is a fairly
normal condition. Any time the motors are moving with the servo drive
disabled, there is pretty much the same effect. This happens any time you
have to hit emergency stop while the machine is in motion. If the servo
drives were to be damaged when you needed to hit emergency stop, that
would be not only a poor design, but a dangerous one.

The only way this could cause a problem is if the power fet driver chips
were not properly biased under this condition. But, it is too easy for
this to occur in other circumstances, so removing the handwheels is
not really solving anything. Hopefully, Mariss can assure you there
won't be any harm.

Jon