[kentdesautel13]

I have a Prolight mill and my spindle motor is starting to act up... ( every once in a while it will drastically drop the RPM's down for a couple of seconds in the middle of milling a piece, and then it will rev back up to normal RPM's again and continue on as normal ) I replaced the brushes and that seemed to help a bit for a while, but now it's doing it again )

So I've decided to look for a replacement spindle motor, but I'm not having much luck finding one.

I'm open to the idea of installing a different retrofit spindle motor, but just need some suggestions on what would be a good replacement option.
I'm ok with fabricating a new top plate to mount a new motor.

Currently it has a Baldor motor
Frame: 25
HP 1 TE
180v DC
5.3 amp
Duty 1 HR
Type: PM

The RPM on the plate doesn't have anything listed..

Thanks much....

Kent

[skrubol]

Issue like that may be in the driver, not the motor.
Weird about the RPM's. Do you know what the spindle max RPM is? Shouldn't be too hard to figure out the motor RPM from that and the geartrain or pulleys.

[kentdesautel13]

My Prolight has been retrofitted, so the spindle motor isn't hooked to my controller. I control my speed with a manual adjustable pot.

This issue doesn't occur very often....( it can vary from once a week.... to twice in an hour.... and then maybe not again for 2 weeks ) in fact I originally thought it may be power surges from my utility company.... but that may be a stretch.
but when it does happen I'm always concerned about my milling bit moving around metal with the spindle not running at the correct RPM.

My spindle motor power comes from a Topaz Ultra-Isolation Transformer 500VA ( so there is a chance that could be causing the issue )


I was also thinking it may be debris from the motor brushes flying around inside the motor ( I tried pulling the brushes out and putting a vacuum hose right up to the hole to try and get any debris out..... but it still seems to happen from time to time )


The RPM is not listed on the motor.... but the Prolight owners manual indicates the max RPM of the Spindle is 5,000 RPM

I normally run the motor at about 60%.... very seldom do I run it at full speed.

Thanks...

Kent

[skrubol]

You still have a motor driver that the pot is connected to don't you?

[kentdesautel13]

Hmmmm…. You just taught me something new.... I haven't heard of a motor driver before...

I will remove some covers on the unit and do some further investigation...

Thanks Much...

Kent

[kentdesautel13]

It looks like I have a kbmg-212d motor driver.

I did some checking and I can still purchase this driver..... so that's an option, unless there is a better option for the driver.

Thanks,

Kent

[gun_mike]

You could try cleaning up the commutator on the motor. Chuck it up in a lathe and gently run a smooth file over it, then some medium grit sand paper, blow it off with some compressed air. This works wonders for me on my 90vdc spindle motor. You have to take the motor apart, but its pretty easy. If you don't have access to a lathe, some careful sanding will also work.

Regards,
Mike