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Two years ago I scored an older Griz tablesaw with a Bessimeyer fence for a sweet price. It sat for a year in my brothers shed, dirt floor and leaks, under a tarp. After we bought a house, it was moved down here. It wasn't handled too gently while it was being transported. I slipped and dropped the motor on the ground. Fast forward another year later and I'm trying to get the shop set up. SO....I get the right plug to put on the new cord. Get the switch all wired up. Got brave and pushed the switch. Nothing. Well thats not true, it hummed for a bit before I turned it off. Checked make sure it could turn freely, left the belt off, and tried it again. This time it hummed and then threw the breaker before I could turn it off. I pulled the little cover off of the capacitor, hoping that it would be an easy fix. No such luck. I can't unplug it without taking the case off of the motor. The wires come out of a solid cap and go into the motor casing. After asking some of the guys at work, I got the name of a couple of repair shops, but I was warned that the bench fees are about $100. A replacement is about $400 from Grizzly. My dilemma is of course money. I can't afford to drop a hundred just to be told that it can't be fixed. If I have to buy another one fine. It'll hurt, but its do-able. I just don't want to spend more than I have to on the motor. After all, I have zoot to buy.
So I turn to you all for advice.

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Aoibeann

There are capacitor start, and capacitor run motors. A capacitor start motor has a centrifugal switch that connects the capacitor to the circuit only for starting. Once the motor comes up to speed the switch disconnects the start circuit. If this is what you have, mabe the contacts are corroded, bent, or damaged to keep the start winding from getting power. This may be a good place to start.

Al

Another thought. Look at the motor connection plate. compare the wire numbers, and see if someone has inadvertantly reversed the polarity of one of the windings. Most people think that alternating current does not have polarity, and it's only a Direct current thing. But AC has what is called instantanious polarity, where current direction is observed at a single point in time. The different windings must have the proper relationships to each other. If one is reversed, the motor will not turn, and it will draw locked rotor current which should trip the breaker rather quickly. This could also be checked by removing the belt, and spinning the motor in the proper direction. Breifly apply power while the motor is spinning, and see if it runs, or quickly stops. If it tries to run, the polarity is correct and the problem is in the starting circuit.

Al

Another thought again. Is this a 220v 3 phase motor, or a 220V single phase motor? It should say on the nameplate. If the motor is designed for 3 phase power, it simply will not run on single phase power( which is all that is available in residential areas) without a phase convertor. Grizzley and others sell these to provide the phase shift required to artificially create the 3 phase power. Static convertors are not extremely expensive, just be sure to match the convertor to the motor horsepower.

Al again

if it turns out that you are in need of a phase converter my old one is available. it is a 5hp and will run the 3hp tablesaw quite easily.

Al its a single phase. I'll give your suggestions ago tomorrow.

Thanks Michael, I may take you up on the offer.

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Aoibeann

lillian, if the motor is single phase you won't need a phase converter. they are only necessary if the motor is three phase and you only have single phase power available, which is usually the case in residential areas.

the symtoms you described are consistent both with trying to run a 3 ph motor on 1 ph power, as well as having a blown start capacitor on a 1 ph motor.

if a creful inspection of the motors data plate reveals it to be 1 ph, i would pull the start capacitor and try replacing it. new one would probably be <$10.

if it is a 3 ph, the converter i have available is a rotary 5hp. works very well. it would be $200 plus shipping.crazymanmichael38964.4690625

Michael, I was looking around pricing a replacement and I can find lots of 3hp 3ph but I found very few 3hp 1ph. I can find 2hp's just about every where. Which is why I thought it might be easier just to go to a 3 ph motor.

I have not wanted to take the case off of the motor, never seen one come apart. If there are small parts for me to lose, I will. I can't just unplug the capacitor from the outside. Now that I'm mostly awake, I'll go out and be brave and take the darn thing apart and see what happens.

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Aoibeann

i don't know about the griz, but some cabinet saw motors have the capacitors under the motor end cover, whilst others have the capacitors externally mounted in a little metal blister. leeson's are this way. i just recently saw a new 1ph 3 hp leeson replacement for a right tilt unisaw on ebay for something like $250. and of course i don't know whether the mounting cleats are the same.

Thanks Michael, I was able to get to the capacitor and disconnect it. It has a slightly burnt discoloration of the case, so I order one from McMaster-Carr. Hopefully this will be all it takes. There are so many things I want to get started on, but I need to be able to cut straight and a jigsaw just doesn't do it for me. So... fingers crossed... this will do it. IF not, I'll be trolling Ebay.

Thanks for your help.

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Aoibeann

The odds of finding a used 3HP 3 phase motor are probably better than finding a single phase. A new 3 phase motor may even be less expensive than a used single phase.
The devil will be in the mounting size and type as well as shaft size. U.S. made motors for the most part have a NEMA standard mounting and shaft size.
You can download a reference chart here. NEMA motors
Nelson

Edit--Hope that the new capacitor solves your problem.
npalen38964.8727893519

lillian, have you any progress to report?

Michael, you have camera in my shop??    The postman just dropped off the box from McMaster-Carr. I was out there scratching my head, trying to figure out how to attach the wires to the capacitor. The other capacitor had a mount with a screw. This one is looks like it wants something to slip over the mount, which of course I don't have and was trying to think my way out of driving across town to get another connector.Aoibeann38969.728125

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Aoibeann

I WORKS!
Thanks guys for all your help.

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Aoibeann

glad things have worked out ok. if you get the urge to handle the capacitor again be careful. they can give you a jolt.

Thanks for the warning.

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Aoibeann