Spindle Motor or drive

[kcarey]

I have one of the early 1100's serial number 33, it has been a great machine over the years. I was running it over the weekend and it had gone through a cycle. I reloaded a part hit the cycle start and no spindle. I have had some problems before with heat but this was something else. I tried to start it in manual mode and it kind of oscillates and make a horrible noise. I spun the spindle to make sure it was not a bind or something like that, it spun free. Is there a easy way to tell if it is the motor or the drive for it? Thanks for any help with this matter

Ken

[saabaero]

Obviously it could be a fault with the drive or motor however since the motor is 3 phase the oscillation and noise you describe in manual mode may be an indication of a bad connection to one of the phases of the motor. Worth checking!

[keithorr]

I had a problem quite a while ago with the spindle not holding speed. The solution was to turn all the pots on the drive board back and forth. Kind of like twisting the knobs on an old transistor radio to clear static coming through the speaker. Corrosion/crude can build up on the pot surfaces and introduce inconsistent resistance. Is your location humid?

Might try making a sketch of the potentiometer settings first so you don't have to re-tune the whole thing.

My machine has worked fine since then.

[twocik]

The other night I had the a problem with the spindle not starting and did a little investigating. I figured out it was the spindle casing latch sensor/switch. I adjusted the screws and pushed it a little closer to the door, done no problems now. Might not be the same for you, but thought I'd mention it.

[300sniper]

i'd guess it's a bad vfd. i had a similar problem when my machine was new. it sounded like the spindle motor was trying to go forward and reverse at the same time making a terrible noise.

here's a link to my problem: http://cnczone.com/forums/showthread.php?t=44096

edit: that was almost exactly three years ago and it has been working fine since.

[kcarey]

I would like to thank everyone for the quick replies, I am going to try what Keitherr suggested but it sounds just like what 300sniper said. If so I think I will upgrade it to the new style control.

[cgroves]

Regarding the door switch that Twocik mentioned I also had a problem with the switch. There's a micro switch buried in there that doesn't have alot of tolerance and doesn't need much to stay in the "closed" mode. This means that the spindle can start spinning even though you've got the door open.
It was a bit surprising when it started... so it might be worth checking if your machines have this "feature" :-).

It can be fixed by opening the switch and bending the microswitch arm slightly.

[Don Clement]

The door switch problem was yet another reason for the Power Draw Bar as the door is rarely opened anymore and certainly not for tool changes.

BTW the VFD upgrade was defiantly worth it for me as the wider range of the new VFD also meant less door openings for belt changes.

Don