Jet Tablesaw tripping breaker , please help

[Craig D Peltier]

I have the 10" 3hp , running on a 30 amp 200 breaker. Been like that for 3 years. No problems. Today try and start it and it trips the breaker. I tried it in another 220 outlet and same thing , but DC runs on both so its the saw.
So when I hit the start button it turns maybe 1/4 inch but looks like in reverse and then breaker trips. I took off the electrical connection cover under the motor. I saw one wire was rubbed to the metal so I electrical taped it and left cover off and it still does the same thing.
The motor smells a bit now.

Im not very good with electrical testers but I have one. Its new if that tells you anything.
I have been cutting maybe 3 or 4 fence boards which were wet in cedar yesterday.

Any ideas???

Thanks

How much is a new motor if needed? Just a guestimate?

[glenn bradley]

Sounds like a starter capacitor (that little bump on the side of the motor). The cap discharges and gives the motor its initial "push" so that the running juice can keep 'er going. Google "bad starter capacitor?" and you will find some folks who may have similar symptoms although maybe not on a saw.

[Craig D Peltier]

Anyone else have any ideas on what I can check/do?

[Craig D Peltier]

Sounds like a starter capacitor (that little bump on the side of the motor). The cap discharges and gives the motor its initial "push" so that the running juice can keep 'er going. Google "bad starter capacitor?" and you will find some folks who may have similar symptoms although maybe not on a saw.

Internet tells me if it were a start capacitor I would hear the motor humming. There is no humm, just a quick bump ( turns the blade backwards about 1/2 inch) and then breaker trips.
Internet was talking about the Cap?? I dont know what that is.

[Rick Christopherson]

Anyone else have any ideas on what I can check/do?Nope, because you already got your answer.

Don't keep trying to start the motor until you get the cap fixed or you will permanently damage your motor.

[Tom Veatch]

...So when I hit the start button it turns maybe 1/4 inch but looks like in reverse and then breaker trips.

Does the breaker trip immediately, or does the motor "hum" for several seconds before the breaker trips? My experience with bad capacitors has been that they fail open and there's an appreciable delay before the breaker trips during which there a very audible 60 cycle hum from the motor while it's trying to start.

If the breaker trips almost immediately, you've got a dead short somewhere in the system. Maybe a shorted capacitor, switch, wiring, or (hopefully not) motor windings. You can check for a shorted capacitor by simply removing the capacitor and trying to start the motor. That simulates a capacitor that has failed open. Make sure the leads from the motor to the capacitor don't short to each other or the motor housing.

If you were getting an immediate trip and now you get the humming motor and delayed trip, the capacitor has failed closed. Don't try to run the motor in that condition any longer than necessary to verify that removing the capacitor does or does not make a difference in what happens. The motor is drawing full startup current for however long it takes the breaker to trip and that's not an ideal way to treat the motor.

If removing the capacitor doesn't change anything start disconnecting things and tying them off until you identify what component is shorting out. Personally, I'd disconnect the motor first and verify the problem isn't in the switch/starter.


How much is a new motor if needed? Just a guestimate?

The 3HP single phase motor for the JTAS-10XL lists from Jet for $550 (plus tax and shipping). I'd look into repair by a local motor shop if it comes down to that. Don't know what the frame size of the motor is, but if it's not a standard NEMA frame (and its probably an IEC/metric frame) you may have trouble finding a new direct replacement from other that Jet repair parts.

Replacing with a commonly available NEMA frame motor, you'll be faced with adapting a replacement motor to the existing mount, which may be no more than a simple flat plate with holes drilled in the proper locations, but will almost certainly require a new drive pulley because of the difference in shaft diameters between IEC and NEMA frame sizes.

Good Luck and be extra careful and safe troubleshooting the problem. Make very sure the breaker's off or the saw is unplugged every time before you stick your fingers into any of that wiring.

[Craig D Peltier]

Does the breaker trip immediately, or does the motor "hum" for several seconds before the breaker trips? My experience with bad capacitors has been that they fail open and there's an appreciable delay before the breaker trips during which there a very audible 60 cycle hum from the motor while it's trying to start.

If the breaker trips almost immediately, you've got a dead short somewhere in the system. Maybe a shorted capacitor, switch, wiring, or (hopefully not) motor windings. You can check for a shorted capacitor by simply removing the capacitor and trying to start the motor. That simulates a capacitor that has failed open. Make sure the leads from the motor to the capacitor don't short to each other or the motor housing.

If you were getting an immediate trip and now you get the humming motor and delayed trip, the capacitor has failed closed. Don't try to run the motor in that condition any longer than necessary to verify that removing the capacitor does or does not make a difference in what happens. The motor is drawing full startup current for however long it takes the breaker to trip and that's not an ideal way to treat the motor.

If removing the capacitor doesn't change anything start disconnecting things and tying them off until you identify what component is shorting out. Personally, I'd disconnect the motor first and verify the problem isn't in the switch/starter.



The 3HP single phase motor for the JTAS-10XL lists from Jet for $550 (plus tax and shipping). I'd look into repair by a local motor shop if it comes down to that. Don't know what the frame size of the motor is, but if it's not a standard NEMA frame (and its probably an IEC/metric frame) you may have trouble finding a new direct replacement from other that Jet repair parts.

Replacing with a commonly available NEMA frame motor, you'll be faced with adapting a replacement motor to the existing mount, which may be no more than a simple flat plate with holes drilled in the proper locations, but will almost certainly require a new drive pulley because of the difference in shaft diameters between IEC and NEMA frame sizes.

Good Luck and be extra careful and safe troubleshooting the problem. Make very sure the breaker's off or the saw is unplugged every time before you stick your fingers into any of that wiring.

Tom thanks for taking the time to type that up. I dont have any questions now. I will tackle it tommorrow. Look for the motor diagram and find out what the cap an capacitor is.

Thanks

[Craig D Peltier]

Does the breaker trip immediately, or does the motor "hum" for several seconds before the breaker trips? My experience with bad capacitors has been that they fail open and there's an appreciable delay before the breaker trips during which there a very audible 60 cycle hum from the motor while it's trying to start.

If the breaker trips almost immediately, you've got a dead short somewhere in the system. Maybe a shorted capacitor, switch, wiring, or (hopefully not) motor windings. You can check for a shorted capacitor by simply removing the capacitor and trying to start the motor. That simulates a capacitor that has failed open. Make sure the leads from the motor to the capacitor don't short to each other or the motor housing.

If you were getting an immediate trip and now you get the humming motor and delayed trip, the capacitor has failed closed. Don't try to run the motor in that condition any longer than necessary to verify that removing the capacitor does or does not make a difference in what happens. The motor is drawing full startup current for however long it takes the breaker to trip and that's not an ideal way to treat the motor.

If removing the capacitor doesn't change anything start disconnecting things and tying them off until you identify what component is shorting out. Personally, I'd disconnect the motor first and verify the problem isn't in the switch/starter.



The 3HP single phase motor for the JTAS-10XL lists from Jet for $550 (plus tax and shipping). I'd look into repair by a local motor shop if it comes down to that. Don't know what the frame size of the motor is, but if it's not a standard NEMA frame (and its probably an IEC/metric frame) you may have trouble finding a new direct replacement from other that Jet repair parts.

Replacing with a commonly available NEMA frame motor, you'll be faced with adapting a replacement motor to the existing mount, which may be no more than a simple flat plate with holes drilled in the proper locations, but will almost certainly require a new drive pulley because of the difference in shaft diameters between IEC and NEMA frame sizes.

Good Luck and be extra careful and safe troubleshooting the problem. Make very sure the breaker's off or the saw is unplugged every time before you stick your fingers into any of that wiring.

Tom the motor at first turned the blade for 1-2 seconds, then as I tripped it several more times it only had enough turn for maybe 1/2 inch of blade rotation. I never heard a hum like it was hard to start.

[Thom Sturgill]

If you bought it new, it should still be under warrantee. Contact Jet tools.

[Craig D Peltier]

I guess I have 2 questions now. If I unhook the capacitor and push start its suppose dot do what?
Second question - If capacitor is unhooked and I wire around the switch , I should rehook the capacitor right? and test the switch? I think I answered the this question as I typed it , but I guess to be sure wouldnt hurt.

Thanks

[Rod Sheridan]

Craig, if you unhook the capacitor, whether it's good or bad, the motor won't start and will trip the breaker.

Not only will you be adding to the thermal damage of the motor, you won't have isolated the problem.

If you're worried that it's a short in the motor or wiring from the motor to the starter, disconnect the motor wires at the starter, put the cover back on and try turning on the saw. If the starter makes a clunk, and doesn't trip the breaker, the problem is in your motor.

Take the motor to a repair shop, where they can diagnose the problem without adding to the damage done to your motor at this point.

Regards, Rod.

[Craig D Peltier]

Craig, if you unhook the capacitor, whether it's good or bad, the motor won't start and will trip the breaker.

Not only will you be adding to the thermal damage of the motor, you won't have isolated the problem.

If you're worried that it's a short in the motor or wiring from the motor to the starter, disconnect the motor wires at the starter, put the cover back on and try turning on the saw. If the starter makes a clunk, and doesn't trip the breaker, the problem is in your motor.

Take the motor to a repair shop, where they can diagnose the problem without adding to the damage done to your motor at this point.

Regards, Rod.

Yes I would like to eliminate the switch as a problem.So when you say disconnect the wires at the switch, did you also mean to say, gator clip those two wires together and then plug saw back in to see if it starts?

[Rod Sheridan]

Yes I would like to eliminate the switch as a problem.So when you say disconnect the wires at the switch, did you also mean to say, gator clip those two wires together and then plug saw back in to see if it starts?

Craig, not to be rude, however when you aren't sure how to tell if a starter or switch isn't working, you probably shouldn't be troubleshooting this. I would hate to hear that you were injured or killed while trying to repair your saw, using advice given on the forum.

I suggest that you take the motor to a shop that repairs electric motors and have them evaluate it for you.

It sounds like a starting capacitor/centrifugal switch/starting winding/broken wire issue.

Regards, Rod.

[Craig D Peltier]

Craig, not to be rude, however when you aren't sure how to tell if a starter or switch isn't working, you probably shouldn't be troubleshooting this. I would hate to hear that you were injured or killed while trying to repair your saw, using advice given on the forum.

I suggest that you take the motor to a shop that repairs electric motors and have them evaluate it for you.

It sounds like a starting capacitor/centrifugal switch/starting winding/broken wire issue.

Regards, Rod.

How did you learn Rod? Well I would like to learn as well. Thats why i ask. I know you werent saying I was stupid but I just want to be sure when messing with electrical.

[Craig D Peltier]

Well it is one of the capacitors. Its a bit melted, all black on the end and its the smell I smelt.
Hope thats all the damage that was done.
Its the 300 Wvac one.

[Jerome Hanby]

That smell is the magic smoke. Once it escapes there's no way to put it back:D

Those caps shouldn't be too expensive. Just make sure you match the value and voltage. I bet Jet will be the most expensive source for it.


Well it is one of the capacitors. Its a bit melted, all black on the end and its the smell I smelt.
Hope thats all the damage that was done.
Its the 300 Wvac one.

[Craig D Peltier]

That smell is the magic smoke. Once it escapes there's no way to put it back:D

Those caps shouldn't be too expensive. Just make sure you match the value and voltage. I bet Jet will be the most expensive source for it.

I have had a very tough finding it to match exact. The 300 volt part. I have been told its okay to go up in volts but not down. Also the Microferds (sp?) which are 40 also can have a variance of up 10% and down 5%.
If anyone disgarees that volts cant go up please let me know.

If Jet has one it will take 3-4 weeks. I may order one anyhow , there less than $10 at electrical supply houses if you can find the right one.

[Steve Clardy]

Just take it to the elec. supply house and have them match it up for you.

They can probably order one in quicker than Jet

[Craig D Peltier]

Just take it to the elec. supply house and have them match it up for you.

They can probably order one in quicker than Jet

I took it to several suppliers and called many others and internet searched for it.Try and find a 300 volt capacitor its tough, then if you do, try to get the UF within 5 points its impossible for me.Theres a allowed variance of about 5-10% percent on the 40 UF part.
I ended up with one from Grainger a 370 volt with the same Uf as the old one which was 40.
I can go to replacement parts for jet but unless you have the part number you cant search it unless theres a breakdown of parts on there product page it says. There is not a full one for this saw a 3hp 10". So if anyone can find out the part number that would be helpful.
Its the 300 volt 40 uf one not the other.

[Craig D Peltier]

The capacitor wasnt the issue I guess. I put new one on. Breaker trips an where the two wire leads to capacitor come out of motor housing there were 2 sparks when button was pushed.
Before I take it to a shop, should I hard wire the power to skip the on off button so see if its that? Or just take in.

[Steve Clardy]

I'd just take it in Craig.
Sparks coming out where the 2 cap wires are at doesn't sound right.

[Craig D Peltier]

I'd just take it in Craig.
Sparks coming out where the 2 cap wires are at doesn't sound right.

yeah the company here says it may be bad if its the windings. Said it could exceed the cost of a new motor.
I see people online have tried to find a replacemnt motor form other sources ( i.e. baldor) but they cant find what frame size it is either. The plate doesnt list a frame size either.

[Rod Sheridan]

yeah the company here says it may be bad if its the windings. Said it could exceed the cost of a new motor.
I see people online have tried to find a replacemnt motor form other sources ( i.e. baldor) but they cant find what frame size it is either. The plate doesnt list a frame size either.

Craig, the motor shop will be able to measure the motor and determine if a standard frame replacement is available.

The "exceeding the cost of a new motor" statement really depends upon the motor. If there isn't a replacement, your only option is a rewind.

Of course it could be as simple as repairing the capacitor wiring if that's all that's wrong with the motor.

The rewind shop will know.

Regards, Rod.

[Craig D Peltier]

Well the shop and myself opened it up. Where you could peer in at the windings and where the wire went in to the capacitor was torched. He said the motor must of got very hot, the windings looked all black as well.Plus the centrifugal switch strike plate was all black. Also where the cord attaches to motor it was reading ground. So there was short also. He said it would of needed to be rewinded. Cost was going to be somewhere upwards of 500. I chose to get a new one for 600 plus it will get here much sooner.
Hopefully not damaged by shippers.Its pretty heavy. Bad break but I need it to make th emoney back :)

Also FYI even Jet doesnt sell that size capacitor anymore nor do they have a part number for it. The 300 volt 40uf. The TS is about 7 years old. When you go up in volts on the capacitor the capacitor usually gets bigger so it doesnt fit any longer. I have heard that some people have used plumbers tape and strapped it on to the motor. Not a very good reselling point when buyer says " Whats that strap on motor holding on?"

He wants me to be sure that the voltage out of wall isnt 208 instead of 220 or 230. He says that this area is notorious for that! Says you can burn out motors like that. I will be checking tonight.

Thanks for all the help.

[Robert Reece]

I'm no master motor investigator, but it doesn't sound like the switch to me. It sounds like a dead short in the motor windings. BTW, the same thing happened to my Jet motor shortly after purchase. The breaker popped immediately. Sounds like a good time to put a 5hp on that TS. I'd check around for surplus motors - you might need to buy or make a plate to adapt your new motor to the current mounts.