Horrible sounding 8x12 motor please help !!

[Dan S]

OK I finished setting up my HF 8x12 today and did some test cuts on it. (chucked up a large bolt.)

When I got home from work today, I was going to try out my new tool. I hit the on switch and the sound was just horrible (please see attached video). Thinking maybe the belt was too tight I took it off and ran the motor by itself. This yielded the same horrid sound. Next I un-hooked the motor and looked it over. The motor has no openings, so no chips have gotten in, the capacitors looked fine, and the wires all looked good. I even chucked the drill up and spun the motor up to speed, and the drill made more noise than the motor did, so nothing is binding.


I know squat about ac motors, does anyone have any idea what could possible be wrong with this thing?

I think this motor might have a clutch could that be it? If need be I can open the motor up and look inside.


Any help would be greatly appreciated.


-Dan S.

[Trapper14]

holy hell thats sounds awful! unfortunetly my fortee is not electronics. lets get some bases covered.

Has the motor been run before?
Does the motor actually turn?
If so does it have torque when it turns?
that may help people answer your question a little better.

it does sound more mechanically bound up than anything, maybe the clutch is stuck, or if it has a brake?

hope I helped a lil bit

Sean

[Dan S]

Sean,

To answer you questions.

The lathe arrived about 2 weeks ago before I went on a business trip. I plugged it in, and it ran fine, nice an quiet. It was running fin earlier in the day when I was making test cuts. It only started making that horrid sound when I got home from work this evening.

The Motor turns as freely as I would expect. I took the fan cover off and I could easily spin it with my finger, and it would free wheel for 2 or 3 seconds.


It had plenty of torque when I was cutting earlier to day. I took 40 thousands of a steel bolt in one pass, and I didn’t even hear the motor strain.

Between my first post and this one, I took the motor apart and looked the internals over. Nothing looked damaged, or like it was scraping.


The motor is marked as a singe phase AC induction motor, if that helps anyone.


I’m even more puzzled now; I have no idea what could be making that much damn noise.

-Dan S.

[dertsap]

what state are the bearings in?

[Al_The_Man]

Is the motor made in the ROC?
My experience so far has been that the Chinese have not yet mastered the art of motor manufacture, (see another recent post).
I know of at least one importer of ROC Lathes, and the first thing he does is replace all the motors before he sells them.
It could well be the Centrifugal start switch stuck in, which keeps the start windings energised and the noise would be 'Electrical'.
Unless you want to replace the motor, take it apart and check the switch before it burns the windings and also the bearings, which are usually woefully bad on these motors.
Al.

[Dan S]

Dertsap,

The bearings look to be in great shape, they actually look to be pretty high quality, I could feel no slop in them.

Al_The_Man,

You must be right, that it was the switch. What would cause the switch to stick?


Either way you won’t believe this. I put everything back together this morning, crossed my fingers, closed my eyes and hit the on switch. To a resounding what the Fu** It ran fine.

I think if it ever makes that sound again I’m replacing the motor, because that sound would be impossible to live with even with ear plugs.

-Dan S.

[Al_The_Man]

Originally Posted by Dan S You must be right, that it was the switch. What would cause the switch to stick?

It is probabally just bad design, I know of a few, myself included that have got motors off the shelf with the same problem, it took two before I got one that worked, I Make sure I only use N.A. or European made motors now.
Al.