×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Determination of windings in DC compound mtr.

Determination of windings in DC compound mtr.

Determination of windings in DC compound mtr.

(OP)
Hello,
I'm working a very old DC compound motor, 6 leads coming from the motor housing.  I cannot open the motor housing, and I am trying to establish which wires go to armature, shunt field, and series field.  There is also a resistor in the circuit, it is external and I assume that it is in series with the series field. I used an ohm meter to measure resistances between leads.  The meter is intended for very low ohms.  In doing this test, I expected to see three resistances, the shunt being pretty high, and the others less than 1 ohm.  For any one lead, there should only be one other matching lead which has continuity.  The others should all be open circuits.  What I found was that a couple of the leads had continuity to several other leads.  All of the resistances I found (7 total) were less than 0.7 ohms.

My conclusion is that the motor has some winding to winding shorts, or at least some insulation leaks.  Is there any other reason that the motor leads would have multiple connections to the other leads?

The motor does run.

thanks
EE    

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources