UPDATE Pullmor Motor Problem.....

Could be a bad segment or lobe. There are three. One of the wires could be broken. I had this happens many years ago. But I got lucky. A wire had come loose from the commuter. It was obvious by looking at it. I reattached  it and all was well.

Steve

Perhaps one of the armature bearings is dry.

sometimes the armature is scratched or has built up carbon built up between the armature segment . polish the commutator and use a tooth pick to clean out the built up carbon between the segments. if you polish the commutator correctly i twill look shiny n smooth like a mirror!

Alan

Measure the resistance between each adjacent commutator contact.  As you go around, they should all be pretty equal, just two-three ohms.  Also, measure them to the rotor itself, none of the windings should contact the rotor body.

Many Thanks Gents for all your replies.

I've followed all the information here.

Communator cleaned well, all lubrication done, segments measure 2-3 ohms...and windings don't touch rotor body.

I have managed to get the motor working well now...sort of.

It does work, however, I have way too much heat build up on the motor winding coil.  It gets very very hot.

Might any of you know what would cause this excessive heat?

And....are there 2 washers and a thrust bearing behind the windings and another set from below where the  C clip slides in place?

Thanks

Dave

If it's getting hot without a significant load, the usual cause is a shorted turn on the armature.  That is not possible to detect with resistance measurements.

The excessive heat John can be felt in the field coil, not the armature winding.

Same diagnosis?.............No load, bench testing.

Thanks

Most likely the same diagnosis, the field in series with the armature. 

I always like placing the ground on the motor frame.  I could not tell from the photos where you were attaching the leads to for sure.  Anyway, thought I'd pass this along.

Dave

@Soo Line posted:

The excessive heat John can be felt in the field coil, not the armature winding.

Does it run warm in both directions equally?

Thanks for the help Guys

Starting over from scratch...in case I missed something.  I am not overly knowledgeable with the issues I am having.

This is a 2 position E unit set up  -   bench testing without the E unit.

In the pics attached.....2 wires are joined from the coil (red and green) top right - 2 wires (longer)  from the coil (red and green) lower left right.

How should I hook all this up for bench testing?  I know things will be different when the E unit is incorporated.

Dave

Actually, all the reverse unit does is switch ground between the red & green wires. Here is the diagram:

Thanks Rob good diagram.

Now the heat issue seems to have abated .....but now it will run for 20 to 30 seconds, shorts...transformer kicks off, then back on for another 30 secs.

At low speed it will run fine for a longer time but stepping up the speed and it quits.

Either direction does the same.

As has been mentioned.....I guess I need a new armature.

Dave

I'm still not sure your test bench is wired correctly.  Please confirm.

Thanks,
Dave

Does anyone have Bob Hannon's book handy, to look up what the typical resistance is for one of these motors?  

Also @Soo Line you mentioned "new brushes."  There are some motor brushes being sold as replacement parts which have a very high resistance.  They are NOT a proper substitute for postwar brushes and will cause excess heat and other issues if used.  If I had caught that the first time I read this thread I would have suggested that you clean the old brushes and put them back. 

A new armature isn't expensive, but in my experience a shorted coil is pretty rare.  Keep trying, don't give up!

Dave G  ..........  The one set of red green wires top right in pic I soldered to one brush.  I applied power to the other brush and negative to either of the remaining 2 red green wires.  One of those for one direction and the other for the other direction.

I did notice your comment on going to the body of the motor for ground but I could not get that to work.

Ted....I had done an extensive search on my issues and did learn about problems with new brushes.  Unfortunately I have already discarded the old brushes.

Thanks

Dave

@DaveGG posted:

I'm still not sure your test bench is wired correctly.  Please confirm.

If it looks like this,, he's good.

Yep.  Should be fine.