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I have a 2003 unisaw. As I shut down the saw I thought I heard a pop. I started it up again and the motor turned on and was spinning but the blade was very slow in turning. The blade rotates easily on the arbor and the belts are intact. Some searching yields opinions that it may be the start or run capacitor. Is it easiest to remove the motor then check and replace it? Any other tips? I haven't replaced one of these before.
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04-05-2020, 04:38 PM
(This post was last modified: 04-06-2020, 11:30 AM by Stwood_.)
Capacitor is easy to replace. Start centrifugal switch isn't bad, Just put the new one in the same place as the old one on the shaft.
Steve
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WaterlooMark 02/9/2020
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(04-05-2020, 04:32 PM)SteveS Wrote: I have a 2003 unisaw. As I shut down the saw I thought I heard a pop. I started it up again and the motor turned on and was spinning but the blade was very slow in turning. The blade rotates easily on the arbor and the belts are intact. Some searching yields opinions that it may be the start or run capacitor. Is it easiest to remove the motor then check and replace it? Any other tips? I haven't replaced one of these before.
Could be the centrifugal switch isn't disengaging.
John
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04-06-2020, 05:20 AM
(This post was last modified: 04-06-2020, 05:21 AM by fredhargis.)
I didn't think of removing the motor as "easy", but it can be done. It might be easiest to take it our anyway, since the problem may be something else. That's what I did when I blew a capacitor. You should be able to determine if that's the problem....mine have always smelled strongly when they popped. Mine was right tilt, if you have a left tilt saw it may (or may not) be a little easier to remove the motor.
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(04-06-2020, 05:20 AM)fredhargis Wrote: I didn't think of removing the motor as "easy", but it can be done. It might be easiest to take it our anyway, since the problem may be something else. That's what I did when I blew a capacitor. You should be able to determine if that's the problem....mine have always smelled strongly when they popped. Mine was right tilt, if you have a left tilt saw it may (or may not) be a little easier to remove the motor.
I had one blow on my 4hp dust collector motor, and it smelled of dead rat. Really bad....
Steve
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How do you determine if the centrifugal switch has failed?
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(04-12-2020, 06:49 PM)SteveS Wrote: How do you determine if the centrifugal switch has failed?
TDKPE knows for sure, but I think you have to take the front bell housing off and check the switch itself. Blow it all out, could just be all gunked up, and then check to make sure the points aren't welded together.
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I was thinking maybe one leg of the 240 not working???????
John
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Does yours have the LVC starter,may start there first just to check to make sure you have 220v. Well I'm late with my guess
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(04-05-2020, 04:32 PM)SteveS Wrote: I have a 2003 unisaw. As I shut down the saw I thought I heard a pop. I started it up again and the motor turned on and was spinning but the blade was very slow in turning. The blade rotates easily on the arbor and the belts are intact. Some searching yields opinions that it may be the start or run capacitor. Is it easiest to remove the motor then check and replace it? Any other tips? I haven't replaced one of these before.
Are you sure the arbor isn't spinning but the blade is loose? Or the arbor sheave sheared its key? Or the motor sheave?
I would start with manually putting some torque on the motor (unplugged, please
 ) while holding the blade with a stick of wood to see if the arbor sheave or blade is loose. To check the motor sheave, you'll probably have to pop off the fan cover and hold the fan gently (don't bend or break it). Pop the belts off and check the set screws, but be aware that there may be two set screws, or even one on top of another.
It sounds odd that the 'pop' happened at shutdown. Capacitors usually blow on start-up, and switches don't usually make any sound when they weld themselves together. Unless it physically came apart as the motor slowed, but still, in a TEFC motor (sealed up), I don't know how much internal sound would get out, and it should still run at full speed with the run capacitor still intact, just have wimpy starting.
(04-13-2020, 05:51 PM)John Mihich Wrote: I was thinking maybe one leg of the 240 not working???????
If one leg is open, you'll get nothing I'm afraid. It's just a 2-wire (hot/hot) circuit; just at double the voltage of the common 120V (hot/neutral) circuit. What comes in through one conductor goes back through the other, reversing direction every 0.0083 seconds (1/120s) at 60Hz.
Tom
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