Start Capicitor

[Turner52]

I have a 1 1/2 hp motor on my table saw. Blows the breaker when I turn it on but starts every time if I reset the breaker and turn it on shortly after that. Thinking start capicitor but have never had one act like this before. No visible damage .Any ideas would be appreciated

[TDKPE]

When it does start, does it snap to speed, or is it slower than normal to start?

If it’s a contractor type saw, with the motor hanging out the back, remove the belt and run the motor.  When you shut it off, listen for the centrifugal switch to close when it’s down below around half speed or less.

Oh, and how many capacitors does it have?

[Turner52]

Goes right up to speed. Everything sounds good. !! start and 1 run capicitor

[Roly]

Is there anything else on that circuit like a refrigerator or freezer or a heater that the load causes the breaker to trip when the saw starts ?   Roly

[mike4244]

I have a 1 1/2 hp motor on my table saw. Blows the breaker when I turn it on but starts every time if I reset the breaker and turn it on shortly after that. Thinking start capicitor but have never had one act like this before. No visible damage .Any ideas would be appreciated

Did the problem just begin recently? Can you plug into an outlet on a different circuit? Could be the breaker is at fault, though unlikely.
If you start normally on a different circuit, then try replacing the breaker. If you do have to replace the capacitors, replace both the run and the start capacitors .
mike

[Bob Vaughan]

Solutions to electrical problems are difficult to determine without being there.
One possible problem area isn't the motor but the switch.  After many cycles of on and off, the switch contacts can corrode from electrical arcing.  The motor wants to suck in lots of current to start but if the switch contacts are corroded, then there's a constriction point in the flow.  If you can, bypass the switch and plug the motor in directly.  If the breaker still trips, then it isn't the switch.

Below are some contacts from an Asian import switch rated at 24 amps.  The eroded contacts were the ones that controlled the current.  They got bad in a hurry.  At the bottom of the photo for comparison is a set of contacts from a NEMA size 1 switch rated for 27 amps.

[attachment=26068]

[Roly]

Have you tried turning the breaker off and then on before starting the motor the first time since it works ok after it tripped and was reset.   This would tell if it is a motor problem or a circuit problem.   Roly

[Turner52]

Seperate circuit. Tried flipping the breaker before turning on. Worked perfect 5 times. Will have to get a new breaker. Thanks Roly. I probably would have changed the breaker eventually, but never would have thought of flipping it before it tripped

[Turner52]

Dug thrugh my collection of electrical parts and found a breaker. Changed out and seems like the problem has bee fixed

[Roly]

Dug thrugh my collection of electrical parts and found a breaker. Changed out and seems like the problem has bee fixed

Good deal.    Roly