Motor Brush questions Testing PDS SEPEX

[JohnnieB]

Check the motor for proper resistance values.

Attached is a checklist from FSIP giving the Ohmic values for the motor and some controller checks.

[pecothern]

Good deal I did check the ohms on the field before and it was in specs. I cant remember the armature though. seems like it was jumping around as I turned the motor I figured the brushes weren't making perfect contact but they definitely are not shorted... I will do that this weekend again.

Can you speak please on the issue with the brushes do they need to be "worn" in to the armature? Would ill fitting brushes damage the controller?

Is running it a while connected directly to 12 volts both forward and backwards a good strategy?

Thanks for your time.

[JohnnieB]

Originally Posted by pecothern

Good deal

1. I did check the ohms on the field before and it was in specs. I cant remember the armature though. seems like it was jumping around as I turned the motor I figured the brushes weren't making perfect contact but they definitely are not shorted... I will do that this weekend again.

2. Can you speak please on the issue with the brushes do they need to be "worn" in to the armature?

3. Would ill fitting brushes damage the controller?

4. Is running it a while connected directly to 12 volts both forward and backwards a good strategy?

Thanks for your time.

1.

2. I'm not all that familiar with all the ins and outs of motor servicing. I have a pretty good idea of what to do from what I've read here, but not how to do it since that's a job I farm out to the professionals.

That said, if the commutator has groves or ridges, it needs to be milled down to an even surface and the spaces between the commutator segments cleaned so adjacent armature windings are not shorted together. Then the motor needs to be ran at low to moderate speed to seat the brushes. To get maximum energy transfer, the ridges and grooves on the commutator and brushes must mate perfectly.

3. If the brush somehow manages to make electrical contact with the field circuit, the controller can be taken out. Other than that, probably not.

4. Probably won't hurt.

[pecothern]

Hey there especially to JohnnieB thank you for all your time and guidance I wanted to make a post to finish up this thread with final resolution. You may recall I did have a Bad controller that I discovered was damaged by the motor. I took the motor apart and found the 2 of the four brushes melted away and one of those wires shorted to the frame of the motor. I replaced those brushes and proceeded to burn up my rebuilt controller. Eventually I bought another controller and took the motor to a local shop where they told me my commutator was shorted from melted brushes bridging the segments or gaps. Also there was some excessive wear and ridges. For $145 they put in on the lathe and cleaned up the commutator and replaced the bearing for good measure. All assembled and works great again. Runs faster and stronger than it has for many years. Fields were fine. Better than spending 650$ on a new motor. My nephew is back in business. Thanks again. Phillip