Return to the Electrical Wiring Forum | Post a Follow-Up

 o
trouble shooting electric motor

Posted by enick (My Page) on
Sat, Sep 8, 12 at 22:05

Hi,

I have a hand held 120 volt pipe threader. About the same size as a 4 1/2" grinder.

It no longer works. I have 120 volts at the brushes. How can I tell if either the rotor or stator is shot?

Thanks,

Nick


Follow-Up Postings:

 o
RE: trouble shooting electric motor

Sounds like a "universal" type motor. Worn brushes is my first best guess. An internal short in the armature is evidenced by excessive sparking at the brushes, odor and reduced speed. Testing for internal shorts on the armature requires a "growler" and disassembly of the motor.


 o
RE: trouble shooting electric motor

Have you removed the brushes to look at them?
When you do, blackened contacts on the armature are a good indication of poor contact. If the contact area is pitted, that's an indication of heavy use with poor contact. Increased sparking is a symptom that the brushes are deteriorating.


 o
RE: trouble shooting electric motor

"Have you removed the brushes to look at them? "

Make sure you mark them so they go back in exactly the same way on the same side they same from.

Swapping or turning brushes (even 180 degrees) is a great way to destroy armatures.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Electrical Wiring Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here