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Thread: Grizzly GO691 Motor Issues

  1. #1
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    Grizzly GO691 Motor Issues

    Today after ripping through 6 sheets of 3/4" plywood for cabinets, my Grizzly GO691 table saw motor is having some issues. I started it up to make my last cut, and it turned very slow and made some weird noises. I would describe the noise as a slight grinding, bogged down noise. I would say the motor was running at about 1/10th the speed it normally does. It was almost like there was some extra resistance on the motor not allowing it to spin up. I haven't had put much time into trying to diagnose the issue, but I did check that the blade rotates freely and blew out the motor on the fan side. There were no bad smells to indicate that something burned up inside the motor. The table saw was purchased new in about 2010. Any suggestions on what to check for?

    Thanks in advance,

    Kyle

  2. #2
    Put an amp probe on it and see what kind of load it is pulling. Also, check the bearings by removing the belt and spinning the motor with your hands. Third, check for proper voltage at the outlet and at the motor. That ought to be a good start.

  3. #3
    Also, look for something obvious causing a mechanical bind.

  4. #4
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    That sounds like the start circuit is not opening up and the motor is not allows to come up to full speed. the is a sort of governor inside that energizes the starting winding and capacitor. If the governor sticks closed, the motor is unable to ramp up to full speed. These get clogged with dust and dirt or sometimes just bind up because they are too tight on the shaft.
    If the start circuit/capacitor were not working of the capacitor were bad, the motor would just hum and not get turning.
    CPeter

  5. #5
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    Thanks for the responses guys. I'm going to go and check a couple of the things you have suggested. Unfortunately, I don't have any way of checking the amperage. Hopefully I'll be able to figure something out soon.

    Kyle

  6. #6
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    Update - after cleaning out my dust collector, which was so full that I got about another 1/3 of a bag full of dust sucked up from what fell out of the plump full bag and dropped out of the canister, I was able to clean out the table saw base and get at the motor. I took off the belts and turned the motor which would spin freely and easily, no binding at all. Checked the voltage at the outlet - 240 V. Took off the fan cover and capacitor covers and blew them out. Both of the capacitor covers were very full of dust. After all of that I replaced everything and fired it up. Still had the same issue. I tested the voltage on the wires after the mag switch and while I was testing it the breaker blew. Obviously that tells me that I'm overdrawing the circuit, but I still don't know why.

    Kyle

  7. #7
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    Have you tested the capacitors? It's not uncommon for a modern cap to go bad.
    Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

  8. #8
    Quote Originally Posted by Kyle Kaldor View Post
    Thanks for the responses guys. I'm going to go and check a couple of the things you have suggested. Unfortunately, I don't have any way of checking the amperage. Hopefully I'll be able to figure something out soon.

    Kyle
    An inexpensive Amp probe will come in really handy in tuning tools. I find it a good way to know if something is running right. i like to Amp motors after I change belts or make other adjustments.

  9. #9
    Quote Originally Posted by scott spencer View Post
    Have you tested the capacitors? It's not uncommon for a modern cap to go bad.
    Bingo...give the man a cigar. FWIW I try to keep my tools really clean, which is difficult in a wood shop I know. This is not so much a lecture as it is a reality of life for me in Ohio, where we have humidity that rusts anything given a chance.

  10. #10
    Normally, a bad cap will keep a motor from starting, it will not cause it to run slowly. And I'm afraid that CPeter is incorrect. There is no governor in the motor. Once a single phase motor starts to rotate it will generally come up to full speed, whether the starting circuit is disconnected or not.

    If the problem is that the motor starts up properly but does not come up to full speed, and has a grinding noise, I'd suspect that the bearings are bad and the rotor is rubbing on the stator. Sometimes the pressure of the belts pulling to one side - if the bearings are bad - will pull the rotor into the stator.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  11. #11
    Quote Originally Posted by Mike Henderson View Post
    Normally, a bad cap will keep a motor from starting, it will not cause it to run slowly. And I'm afraid that CPeter is incorrect. There is no governor in the motor. Once a single phase motor starts to rotate it will generally come up to full speed, whether the starting circuit is disconnected or not.

    If the problem is that the motor starts up properly but does not come up to full speed, and has a grinding noise, I'd suspect that the bearings are bad and the rotor is rubbing on the stator. Sometimes the pressure of the belts pulling to one side - if the bearings are bad - will pull the rotor into the stator.

    Mike

    Makes sense. Bearings were one thing I suggested, which is why I wanted the OP to pull the belt and try spinning the motor by hand. Normally when bearings start to go i can feel it when I turn a motor by hand...

  12. #12
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    I have to differ. I had a Grizzly motor on my milling machine that did just that. the starting circuit was sticking closed and kept the motor from spinning at full speed. I rebuild motors and machines as a source of income and this is not an uncommon problem. If the motor has two capacitors, one will be the start and one will be the run. It is possible that the run capacitor is bad. but I still think my original diagnosis is worth checking out. BTW, there is a governor in most larger single phase motors to control the starting circuit.
    CPeter

  13. #13
    Quote Originally Posted by CPeter James View Post
    I have to differ. I had a Grizzly motor on my milling machine that did just that. the starting circuit was sticking closed and kept the motor from spinning at full speed. I rebuild motors and machines as a source of income and this is not an uncommon problem. If the motor has two capacitors, one will be the start and one will be the run. It is possible that the run capacitor is bad. but I still think my original diagnosis is worth checking out. BTW, there is a governor in most larger single phase motors to control the starting circuit.
    CPeter
    I also have a capacitor tester among my shop tools. Paid sixty dollars for it several years ago and it has come in very handy...

  14. #14
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    Thanks again for the help. Can someone walk me through how to check a capacitor and what I'm supposed to be looking for. Is this done when the motor is powered up or off? By the way I'm fairly certain it's not the bearings. The motor would spin freely with no play or grittiness, very smooth.

    Kyle
    Last edited by Kyle Kaldor; 02-12-2017 at 8:21 AM.

  15. #15
    Test it with a capacitor gestor or just buy new capacitors for the unit. Capacitors probably less than ten dollars apiece at an electrical supply house.

    Also, double check all of the electrical connection points inside the saw. Table saws create lots of vibration and that creates havoc with connections.

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