surplus motor rebuild?

[JFettig]

lately my motor has been acting up, I narrowed it down to the motor anyway, I opened it up, and the braided wire connecting the stranded wire to the brushes looks quite fried.

the problem was the motor was cutting out at higher speeds, now its cutting out randomly and sometimes doesnt even start at all.

Basicly, looking at the pic, I dont even know how easily I can connect stranded wire to it, and what is the reason they use braided wire on that part? It shoudl be ok and all to use stranded wire correct?

Jon

[Al_The_Man]

I would use a soldered butt splice from the braided to stranded wire and cover the joint and braid with heatshrink tube. Braid is used for brushes because of its flexibility. Check the brush length and spring tension. Also I would tie-wrap the wire to the end mount to prevent movement & vibration. Where was the brush lead terminated before?
Al

[H500]

The main advantage of braided wire is flexibility. The individual filaments are typically much thinner, so the braiding keeps the strand together. A convenient source for the braiding is the desoldering wicks which is available at electronic stores.

I don't think your problem is the wire itself. More than likely, your carbon brushes are worn out. Take a look at them. They should solidly push agains the rotor part.

[JFettig]

I got the motor like that. so thats how its been, The fried part is right at the brush.

Jon

[Al_The_Man]

If the braid is disconnected or fried at the brush, one way using the piece of braid you have is to solder one end to the stranded wire and the other end, if it has come disconnected is to solder a small copper or brass washer to the end of the braid and place the washer between the brush and the spring tensioner, This may get you working until you get a new brush.
Al

[Mac T. Knife]

Finally somethingI can help out with,,, (Stepper motor problems had me pulling my hair out,, which I can't afford!) Sounds like you have an accumaltion of brush dust haniging up the brushes n the brush hoods,,, If you can, remove them and clean the hoods, you may have to clean up the sides of the brushes with a file to allow them to move smoothly. Myself, after cleaning up the brush hoods, I would see about soldering a wire to the brush hoods to improve the electrical connection. It would also add a little heatsinking to the brushes them selves. 12 years of racing electric rc models, I've picked up a little info on brushed motors.

[JFettig]

Im not exactly sure what you mean, but the wire that goes into the brush is kinda just stuck into there, and right where it goes in is where the wire is fried. I will try to somehow get some wire in there.

Jon

[miljnor]

Brushes are Very cheap. I would just replace them if thats an option. I believe that mac was saying to solder an additional point of contact on to the brush holder, not the brush itself.

I could be totaly wrong. but if there is brush holder (or guideway) is metal this makes sense as long as its isolated from the rest of the case.

[JFettig]

thats a reletively good idea, the problem with buying brushes is it would be pretty hard to find the right ones for this motor. Ill work on it soon.

Jon

[miljnor]

I might be able to help you out there. what is the physical size of the brush. or better yet the treadmill the motor belongs to. I have a buddy the know every peice of cardio equipment used (its like a magical ability or somethin) and he also fixes most of them and if he dosn't personally have the brushes he can probably get them.

[Mac T. Knife]

Any repair shop/motor repair shop should bee able to find a brush that fits,,, It appears to be a carbon brush,,, some of the cheap imports use graphite brushes,,, Really good for causing the brush to hang up in the hood. As for adding a wire to the brush hood itself,, If you were to measure the brush shunt gauge, and compare it to a char for amp draw per wire gauge, you would most likely find that the shunt is just barely big enough,,, and for your application not enough.

[JFettig]

You see where the two wires connect together? I just chopped the braided stuff off there and jammed that peice in the hole and it seems to hold well. I made few parts today. Some day itll hit the end of its flexibility and not make contact, but untill then, Im sure its good enough

Jon