table saw

[bglad]

I have an older Craftsman table saw which the motor started running at a low speed and with no torque. Would anyone know what the problem would be? In order to get the blade to turn I would have to manually spin.

 

[softailgarage]

How old? Specs on the motor?

 

[bglad]

I'll have to get the specs. Could be about 30 - 40 years old.

 

[sands35]

Is it wired for 120 or 240? Sounds like you dropped one side of a 240 wired motor.

 

[nehog]

Is it wired for 120 or 240? Sounds like you dropped one side of a 240 wired motor.

A motor wired for 240 volts would not use neutral, and it would not be possible to 'drop' one side.

IMHO, the OP has a failing starting capacitor perhaps.

 

[bglad]

120v.

 

[shoot summ]

A motor wired for 240 volts would not use neutral, and it would not be possible to 'drop' one side.

IMHO, the OP has a failing starting capacitor perhaps.

Winner...

 

[bglad]

I did replace the capacitor (sp?) about 5 years ago. Not quite sure but I think it was the same problem. This time I was using it for about 1/2 hour and it started to stall when I was cutting some wood. Finally it wouldn't turn at all and tripped the circuit.

 

[sands35]

A motor wired for 240 volts would not use neutral, and it would not be possible to 'drop' one side.

IMHO, the OP has a failing starting capacitor perhaps.

Yes, correct. I was not.

 

[theoldwizard1]

Put a meter on the outlet and watch the voltage when you turn the switch on. It should not drop more than about 10%.

My Dad had the same problem (used a stick to spin the blade to get it started). He found out that the voltage was dropping to 90V when the saw was starting. It took him awhile, but he eventually convinced the power company that they had a problem (after they validated his wiring was adequate for the load) and they did replace a transformer down the line.

 

[zkling]

I did replace the capacitor (sp?) about 5 years ago. Not quite sure but I think it was the same problem. This time I was using it for about 1/2 hour and it started to stall when I was cutting some wood. Finally it wouldn't turn at all and tripped the circuit.

Hum, so it quit while running? That normally wouldn't signal a start cap issue. The start cap is there just as it sounds, to start the motor. It should run fine once spinning even if the start cap is bad.

Can you post a pic of the motor? Is it an older dual saft, with silver, engine turned finish cover in the middle of the motor? I would check the line voltage as well as the power cord to the motor. Stay safe.

 

[softailgarage]

Blade is free right, nothing tangled up in the arbor? Maybe the Old Wizard is on to something

 

[wyliesdiesels]

Is it wired for 120 or 240? Sounds like you dropped one side of a 240 wired motor.

If a 240v SINGLE PHASE motor lost one leg of power it would no longer work. On the other hand, if a 3 phase motor lost one leg, it would continue to spin but at reduced power and would overheat due to over-current!

 

[mm08822]

When the start winding, capacitor or centrifugal switch is bad, rotating the blade will get the motor running in the direction you spin it. The start winding gives direction and starting torque until very close to rated speed at which time the cent switch cuts out. Then only the run winding is producing torque.

Since you were cutting wood at full speed when the problem occurred, it sounds like the run winding insulation got too hot and possibly melted some of the insulation and now some turns are shorted out in the run winding. This will weaken the magnetic field and may still turn the motor at no load, but can't deliver the torque needed under load. As the motor stalls, it will cause the current to go way up and trip the cb. Sounds like your needing a new motor.

You may still be in luck if the motor is a cap start/ cap run design. Could be the run cap is going/gone. (I doubt you have this type.)

 

[ratman2]

I bet the motor needs to be cleaned.

 

[kbs2244]

"I bet the motor needs to be cleaned. "

Bingo!

Table saw motors live in a very bad spot.
Pull it out and do a good clean and oil job.

 

[G_P]

Does the arbor turn freely with the belt removed? Maybe a bearing has gone bad.

Sent via carrier pigeon.

 

[bglad]

The motor does turn freely. I messed with it the past few days. I can't remember the previous problem but when I replaced the capacitor it was fine. That was probably about 10 years ago. This time it does not want to come up to speed when I spin the blade. It'll turn but at a speed where I can count the teeth as it rotates. The last time I tried it wouldn't even rotate.The motor was fairly clean. Probably is the motor considering that it's old. I'll try to get a picture of the motor. Thanks for the help from everyone.

 

[G_P]

Open up the motor. Blow out all the sawdust and check the centrifugal switch. Relube the bearings. Replace the capacitor. Run it with the belt off and see if it gets up to speed.

Sent via carrier pigeon.

 

[bglad]

I'll give it a shot. Then I can get a few pics of it also. Have my coffee and heading out into the garage!

 

[bglad]

Didn't bring my camera but the motor is fairly clean. There was some dust, inside the windings was clean. The motor turned freely. I checked the capacitor and it seemed to have an oily residue on it, so I'm going to start with replacing that first and see what happens.

 

[bglad]

Ordered the capacitor yesterday. I'll let everyone know how I make out when I get it installed.

 

[bglad]

never got around to getting some pic. Anyway received the capacitor in the mail yersterday and installed it. Guess it must be the motor. It will turn but not come up to speed. That will be another rainy day project.