Foredom help

N

Nsewell

Joined
Mar 26, 2017
Messages
86
I recently got a used cc foredom from the big auction site. Worked great till I broke the shaft. So I got a maintenance kit for it and installed the shaft and greased per instructions. It says to let it run for a few minutes to distribute the grease, so I checked the brushes before I let it run and they were barely wore. I then unplugged it from the pedal ( it was a little corroded) then plugged it into an extension cord and it run full speed for a few minutes. I stepped out of the shop for 2 or 3minutes and when I came back it was arcing or shorting out a little bit inside the motor. I went ahead and changed the brushes after that but no change. I've blown it out and looked around inside but I don't know what to check. It seems to get worse every time I try it. Any suggestions?
 
Can you take a video of the sparking? You're always going to see SOME arcing/sparking inside a brushed motor, where the brushes contact the commutator. Cleaning the comm and brush holders might help to a degree. Is the motor still coming up to a full and constant speed? Did you happen to get some grease on the commutator perhaps?
 
It's sparking and popping a lot more than normal and sort of stalling while it's sparking before it gets to full speed. No grease on commutator.
 
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Try spraying some electrical degreaser on the comm and brush holders, and make sure the area were the pigtail lugs make contact are clean. Also, if your brushes are square, make sure that the concave surface on the comm end is following the curve of the commutator and not turned 90 degrees the other way. (the newest foredoms are rectangular, so they can only turn one way).
Lastly, make sure the end caps are tight so that you have a good lug connection.
 
Also, make sure they are put back in the same orientation. The curve gets work to fit, and may be directional. It should wear in in a few hours run time (which may be weeks of use).

+1 on Drew's suggestion to blast the commutator and all clean with circuit cleaner. Let it drain for a few hours and then re-install the brushes and run it at half speed for a while. I like the CRC brand products.
 
Be aware that if the unit is old, the commutator may be worn out, in which case it will arc a lot. Cleaning usually helps, but as long as it runs OK, the arcing isn't much of a big deal.
 
Nsewell said:
I recently got a used cc foredom from the big auction site. Worked great till I broke the shaft.
Click to expand...

You start with mechanical problem and end up with electrical problem .... think about that what and where you done wrong......:)
 
It was running fine without the arcing until I removed the brushes to check them and it ran fine for a minute or 2 before it started.
 
Your brushes are turned the right way, correct?

Also, it should take a little bit of effort to shove the springs into the holder holes, before putting the end caps on. If there's not enough tension (or rather, compression) on the brush springs, they won't make good contact. Worst case scenario, there's a break in the winding somewhere, or something wrong with the commutator. If it was running fine before hand, however, I have a hard time thinking it's not something more simple than that.

Did you have to move/remove the commutator when you changed the shaft? Is it turning freely?
 
They are turned correctly. I didn't remove the commutator to replace shaft, but I did after it was arcing badly to blow it out. I figured it was a bad idea but it was arcing so badly I had nothing to lose. It does the same after I put it back together as it did before. It does spin freely.
 
It lives! I checked the brushes again and I think I had the spring pinched and the lug was not making contact. This was the first time I have ever changed motor brushes on anything. After I made sure they were in correctly, I plugged it in and it arc a little bit, settled down and ran smooth. Thanks for all the help.
 
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