Old DC Motors not used

[lukin1977]

Dear Experts

We have a few old DC motors (see pictures) that have not been used for many years.
Can anyone tell me how to proceed to put them back in working conditions?
As you can see the windings are in very bad shape (dirt, rust and moisture acummulation)

Thanks in advance!

 

[edison123]

If the insulation is flaking off, time to rewind. If not, clean, dry out and test.

Muthu

http://www.edison.co.in

 

[waross]

And look at the bearings. It looks as if a bearing was failing.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

That's the commutator Bill.

 

[edison123]

Bill's commutator phobia is a well-kept secret. Now you have spilled it, Scotty.

Muthu

http://www.edison.co.in

 

[lukin1977]

My plan is to:

1st clean as good as possible using vacuum machine, light brush and air gun
2nd Dry for 3 hours at oven at 105 ºC
3rd Varnish the whole windings
4th Dry at oven for 2 hr at 80 ºC

 

[waross]

I am a little concerned with the scuff marks and missing paint inside the stator and on the surface of the rotor, not the verdigris on the commutator.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

Amusing off topic side story triggered by Bill's comment; a friend had copper gutters installed on their house this past summer, I just saw them and they were already green. Turned out they PAID EXTRA to have the verdigris "added"!


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[edison123]

5th - Test all windings and brush holders before assembly.

Muthu

http://www.edison.co.in

 

[lukin1977]

edison123: Please explain how do you recommend to test the windings?

 

[edison123]

Armature
IR value. Bar to bar DC resistance. Surge comparison test. Commutator roundness.

Both Field windings
IR value. DC resistance. AC pole drop test and/or Surge comparison test.

Brush holders
IR value.

Muthu

http://www.edison.co.in

 

[panter]

At disassembled DC motor is good to check the polarity of the main and auxiliary poles .At rotor you should check possible inter-turn shorts .
Good luck !

 

[lukin1977]

Update: The motor could not been restored.

So it has been fully rewinded and it is working OK