Re: [CAD_CAM_EDM_DRO] Re: Dead Grizzly speed control/VFD

Ray Wins!!! Thanks!

When I got home today, first thing I did was open the "switch panel"
which
has the motor leads terminating in it. I clipped my meter on them and
ran through the power range.... 44V DC to 110VDC. Drive looks good.

Next, I powered it up (of course it didn't spin up) and slowly turned
the
spindle by hand. Around 3/4 of a turn around, the motor "caught" and
the spindle spun perhaps 1/16 th of a turn! Definitly looking like
brushes.

Then I unplugged everything and removed the brushes (which I had not
really noticed before)... and pulled them out. Each was around 9/16's
of an inch long, and one had a pretty high carbon buildup. (The other
had some, but not as much). I cleaned them up with some emery paper,
re-installed them, and viola! It's running smooth as ever. (I only
wish I had the sense to do that when it first started (I had paused EMC
and re-starting the part would have been much easier!).

Back to running the poor mill 40 hours a week (I've been machining robot
parts pretty hard when I get home at night)... Someday I'll have room
for
a "real" machine.

Thanks folks. This group is simply amazing.

murph


Ray wrote:

>
> John M.
>
> If this is the G8689. It uses a DC motor with brushes. I'd suspect the
> brushes before the drive. If one brush hangs up it will cuase the motor to
> stutter and draw a lot of current when contact is made.
>
> For these, a VFD is no good but a low cost DC control might work. You
> would need to compare V and A.
>
> Ray
>
> From: John Murphy <john@...>
>
> >I've got the tiny grizzly mini mill, and my drive has cut out. I'm
> >going to try to get it replaced under warranty, but I'm not willing to
> >go through the trouble of shipping the mill back as it says they
> >might do under their warranty.
>
> >The symptoms were fluctuating speed and horrible blinking of the
> >flourescent lights in the shop, then it died. I waited a couple of
> >hours, tried again, and it started up OK, but erratic, before it died
> >again. Now it won't start up at all.
>
> >If I'm going to replace it myself, can anybody recommend a compatible
> >VFD, perhaps something with a speed control input?
>
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