Electrical help please

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Monty

Group Buy Coordinator
Joined
Mar 4, 2005
Messages
8,573
Location
Pearland, Texas, USA.
I have a Jet JSB-10L buffer that is about 7-10 years old. The start capacitor went out. It is a 300mf/120v capacitor so I replaced it with a 275-324mf/125 capacitor. It still just sat there and hummed until I manually spun the wheel. I took both capacitors back and had both checked. The original one showed "dead" while the new one shows "good". Put the new on back in and it still just hums when I throw the switch. There is nothing else I can replace in the lower housing where the capacitor sits. What's my next option besides buying a new buffer?
 
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Try a little wd40 on the shaft where it goes into the housing, There may be some rust or dirt build up there. Spin it once and than see if it will go when u turn it back on.
 
If you have the owners manual - on the other end of the motor housing from the capacitor there is a centrifugal switch (it might be item #5) that swithch should be closed when the motor is starting and open when the motor gets to about 3/4 speed. If that is stuck open, you'll probably get the symptoms you're seeing.

Also you should be able to call Jet and talk to someone who could help you since this machine seems to still be in production.
 
there is a centrifugal switch (it might be item #5) that swithch should be closed when the motor is starting and open when the motor gets to about 3/4 speed. If that is stuck open, you'll probably get the symptoms you're seeing.

Smitty; If the switch doesn't open when the motor is spinning, it will cause the capacitor to overheat and fail after a time (minutes, hours?). The switch is closed when the motor is at rest, and opens (taking the capacitor out of the circuit) when the motor gets up to speed.

Monty; A good idea would be to take the motor to a motor repair place and ask them to look at it. If you are confident in your mechanical skills you can disassemble the motor yourself.
 
there is a centrifugal switch (it might be item #5) that swithch should be closed when the motor is starting and open when the motor gets to about 3/4 speed. If that is stuck open, you'll probably get the symptoms you're seeing.

Smitty; If the switch doesn't open when the motor is spinning, it will cause the capacitor to overheat and fail after a time (minutes, hours?). The switch is closed when the motor is at rest, and opens (taking the capacitor out of the circuit) when the motor gets up to speed.

Monty; A good idea would be to take the motor to a motor repair place and ask them to look at it. If you are confident in your mechanical skills you can disassemble the motor yourself.
There is also a starting coil on most of those motors that must be in the circuit for the motor to start...but at any rate a failed switch could be the cause of the problem. He did say that when it didn't work after he changed the Capacitor that the new capacitor checked good and the old one checked as "dead".
 
The centrifugal switch contacts can be burnt or held open by sawdust. File the points with fine sandpaper or a fine file. Blow the trash out of the switch , the weight, and springs.
 
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