Hello,

I have been trying to learn more about the electronics world and going back to school for electronic engineering. I often find the best way to understand things is by hands on.

Recently I acquired a belt sander that had a humming noise coming from the motor. I thought it could be the capacitor so I purchased a new one plugged it in and still no fix. Upon further investigation I noticed the wire coming from the capacitor going back into the motor windings had several portions of exposed wiring (maybe a short)?? As I set the cap down, the wire disconnected from the motor windings and I cannot see where exactly it came from and I am wondering if it is possible to insert a new piece of wire back into the motor? Any help is very much appreciated! Go easy on me (newbie).




The wire in the pictures above is in the general area of where it came out of. Just not sure exactly where it got disconnected at and I didn't to undo any windings or anything until I get a better opinion. Thank you again!

 

You should be able to replace it ensure there is no bare connections if soldering the lead on, heat shrink tubing could be used for insulation here.
Use a conductor from an old extension cord etc.
Check all connections for any possible continuity to ground (frame).
Ensure there is no short circuit of windings at the repair site.
Max.

 

From those pics it's difficult to tell much. Max is far better than I on motor windings, start/ cap stuff, but I'd say this is a great learning opportunity for you to figure out as much as you can, maybe even your own question. You know those stator windings must connect to the line, perhaps you don't realize that there is usually a thermal switch as part of the circuit, for safety or overload purposes. The capacitor is in the circuit. It is not clear from what I can see whether this is a brushless motor, or if the capacitor is switched, but you have all the pieces to find out. There are several basic types of single phase A/C motors, and are often known by their pieces, such as "permanent split capacitor" or "capacitor start, capacitor run" motors. Looking at all the components you have closely will help you, and Googling that stuff will bring you simple schematics of them, which will show you what gets connected, and how.

I don't tell you this to blow you off, but merely to bump you in a good direction to go through the appropriate steps to understanding these things, and how to do it again for similar things. These threads can turn into lengthy affairs with plenty of missed details and misunderstandings and frustration. "Blind men and the elephant" ordeals, so to speak.

 

To me the contrasting colrs of copper and black SUGGEST a burned winding. The "insulation" used on "magnet wire" is usually "Formvar", a insulation resembling varnish, and it will turn black if overheated. It is insulated. Just very thin and somewhat clear.

There is a thread on AAC, where an aggressive attempt to rewind a blender occurred.