Re: re:Servo not stalling, a problem?

Ballendo:

So, what you are saying is: don't try to save money on the limit
switches! hehe

You have instilled in me a healthy respect for the mechanical monster
I'm creating, and I thank you.

Ron

--- In CAD_CAM_EDM_DRO@egroups.com, ballendo@y... wrote:
> Ron,
>
> I should prob'ly wait for the more learned to answer this but I
put
> my foot in mouth as good as the next guy, so here goes...
>
> By definition, a servo is a "feedback" driven device.
>
> ANYTHING which causes the "loss" or "incorrectness" of this
required
> feedback, CAN lead to axis "runaway". This could be the unplugging
of
> a connector(or a wire breaking), a software glitch, or a servo
> drive "error" (not likely in most modern drives, but a "classic"
> problem). But the careful "balancing act" that IS a servo system
can
> and does become unbalanced at times. Sometimes it is just a slow
> moving problem, or a simple adjustment... Or...
>
> If (when!?) the axis "runs away", the servo motor will be trying
> to "get somewhere it can't", either mechanically or electronically.
>
> Usually this means the FULL FORCE of the motor is being applied
where
> it shouldn't be... Since the motor keeps trying to "get there from
> here", heat and/or pressure build up and... motor burns out/ drive
> fails/ machines(or people)get crushed/ tools break/ parts are
ruined/
> etc.
>
> Obvious results likely.
>
> Hope this helps.
>
> Ballendo
>
> P.S. I've added some theatrics to make a point, but these things DO
> happen with servo systems! LESS so with modern controls/systems,
but
> STILL do happen... There IS a reason for that BIG RED BUTTON!!
>
> >I'm considering switching my design from steppers to servos. I've
> >read that a servo NOT stalling can cause design problems. What
> >problems are these?
>
> Thanks,
>
> Ron