Re: [CAD_CAM_EDM_DRO] Servo motors with Geckos get hot when idle.

tig415 wrote:

>
> Hi
> Sometimes one of my servos will get scorching hot when I leave them engaged but idle over a period of 30 minutes to an hour. It doesn't happen all the time and it's not the same servo every time. When I'm running them they don't get hot at all.
> Any ideas on this?

Hopefully, Mariss will answer this, but I would guess the problem is that
an oscillation has developed between the motor and encoder. Later
Gecko servos have an anti-hunting feature built in, I don't know if
yours are that generation or not. Does the motor hum or whine
when this happens? What is the coupling between the motor and
encoder? Is there any looseness or play in that coupling?

My guess is that if you were to move that axis just a tiny bit, so it
was sitting on a different place on the encoder wheel, the motor
would cool down.

One other possibility is that you have binding or tight spots in the
screw or machine, and the servo drive is trying to move the encoder
just 1 or 2 counts, but the machine is resisting that move. The loop
gain is not high enough to break the friction at that point, and so
the drive applies moderate current to the motor, and it just sits
there. If the motor has a lot of armature resistance, it will get hot
in this stalled condition. (This is why I recommend using motors
with the lowest possible resistance for servo drives.)

What motors and encoders are you using?

Jon