Electric motor problem

[chuckey]

About the screw that was clamping via a phenolic board thickness. This is a very bad thing to do, its obvious on this web, but in my job I wrote specs for capital electronic kits and this was one of the things we were very hot on! - I have just had the same problem on my VW Passat electronic handbrake switch, nearly had TWO serious accidents by the car rolling away when parked. I started to have doubts about if I had put it on. When my mechanic replaced the switch - 100% reliable, I took apart the old switch and some printed circuit connections were riveted through with the thickness of the PCB between the holding surfaces. NOT SOLDERED.
Frank

[KellyJones]

Electric motor problems must be contagious. Mine on the lathe started making a "sizzling" sound this morning and the shop started stinking. Had my son momentarily start the lathe while I watched the motor. Sure enough, the magic smoke was escaping from one of the two capacitors. Took the cover off (after unplugging the lathe) and found the capacitor burned. Fortunately, Grizzly has a spare that I have ordered.

Any idea why this might have happened? The lathe is only about 10 years old, with less than 200 hours on it, and stored in a semi-heated shop Anything in particular I should look for when I replace it?

thanks for the thoughts.

[JackF]

If the motor is the one that came with the lathe it will be of chinese decent. That more than likely means chinese caps. I would look for US made caps. I had to replace the motor in my G0554 lathe after about 2 years, don't know if it just gave up the ghost because of the caps or???

Jack.

[KellyJones]

Ok, got the motor off the lathe. Thought I could plan out the job while waiting for the replacement capacitor. Definitely fried. Found a couple of loose screws in the electrical box on the motor, but no signs of overheating. Looks like the capacitor was soldered after the wires were pulled though the housing. No obvious easy way to pull the wires back through. Thought I would check with the forum to see what I would be facing when i pull the end cover off. Spring loaded parts that fly across the room and land under the most inconvenient table? Gnomes? Nothing? Any thought would be appreciated.

[hammermill]

caps fail because they get dryed out or are exposed to a voltage higher than the dialectric can handel, this can be in a very short time. this leads to a fault,heat and failure. electroletics in power supplys if over volted can explode in a very impressive manner. buy a set of spares some machines just love to kill em at bad times.

A stick start switch will also cook one clean the contacts and inspect it in the motor if it has one

[Mr Ron]

Capacitors used on motors that start heavy loads such as air conditioners and compressors usually have the highest failure rate due to the high inrush current at starting.

[steamin10]

I have some experience with Chinese exploding motors. While you are fiddling around, do a check on the leads and ring everything out. You may find a winding is unequal or heavy on the current. As suggested, Chinese caps may not be the best. Go through and do a for real preventive maint checkout, including lubing the bearings if possible. Obviously if you determine flaws and fix them, you will be light years ahead. Caps are cheap, so toss if you think they are a problem.

[KellyJones]

Success! Got the lathe running again. Small soldering job to install the new capacitor. Opened the motor to inslect the starter switch and windings. No evidence of buring, arcing or other bad stuff. Thanks for the comments.