Dayton grinder motor vibration

Something bad has happened to the motor mechanically. It is possible you have a loose/cracked rotor bar or end ring. It could also be that the field windings are loose. I've had several motors like that. I have never found a solution. You can take it apart and carefully look at the rotor (the part that spins in the middle) to see if you see anything cracked or loose. You might get lucky and be able to secure it somehow. Also look at the stator (the part that sits still with a coffee-can-like hole down its axis) to see if you see anything that has come loose. While you're in there blow things out with compressed air to see if that makes anything wiggle.

Grant Erw> I have an old Dayton grinder, 1800 RPM motor. When it is running, it

Did you check for loose fasteners holding the stator into the housing?

Or any other loose internal parts which might be vibrating in response to the ac magnetic fields in the motor?

Might also be loose windings on the stator (rare, but I've encountered it more than once in my life.) The windings are usually secured by varnish or some other "glue". I quieted one motor down last year by taking it apart and slopping some left over "auto repair" fiberglass resin into the stator slots and all over the windings where they emerge at the ends of the stator.

Happy New Year,

Jeff

-- Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place the blame on."

Thanks for the thoughtful responses. Looks like I have another project on my hands!

-Spencer (Rat of Brass '83)

One other thing to check, is the start winding switching off? The start winding is usually controlled by a syntrifugal switch that turns it off as it gets up to full speed. These can jam on, and the motor will hum if it runs with the start winding in.

regards,

John

Yup..been there, done that. Though in my customers case..third time was the time it let out all the magic smoke. Then he calls me.

Gunner

"Gun Control, the theory that a 110lb grandmother should fist fight a 250lb 19yr old criminal"

Are the bearings good? Is there any radial play? Some motors will buzz very loudly when energized because the rotor is being pulled into the stator by the magnetic field. If there are signs of scraping on the rotor, that is a strong indication the bearings are worn.

Jon