Motor Tripping Breaker?

[Mortiser]

Need a little help here from the motor guys or electricians.
I have a jointer/planer with a 1-1/2hp, single phase, 115V Dayton motor on a 20A circuit. When I first start the machine, it trips the breaker. This is a 100A Square D panel and the only other thing running in the shop is lighting on a separate circuit. In other words, there is no other load in the shop at the time. I am using a 10 foot, 12 gauge extension cord. The wiring on all circuits is correct. It is on a GFCI outlet but the GFCI does not trip. After resetting the breaker at the time, the motor starts up without an issue. After it's been running, if I turn off the machine and then start it again within five to ten minutes, it starts up without tripping the breaker. If however, it's longer, say 20 minutes since it last ran, and I start it again, it trips. I have tried it on another similar 20A circuit and the same thing happens. These are new breakers. The motor is approximately twelve years old but only used in a hobby shop.
Does this likely indicate I have a bad motor capacitor?

Thanks for any help.

 

[waho6o9]

Maybe try a 10 gauge extension cord. 

I'm not a motor guy or an electrician.

Best of luck/

 

[squall_line]

These are new breakers.

Are they Arc Fault breakers?

 

[Bohdan]

Replace your breaker with a D curve breaker. These are designed to handle motor startup currents.

 

[Mortiser]

[member=75217]squall_line[/member] - no, they are not arc fault breakers. I would have ditched that early on. Just don't have much success with those around motors. Thanks.

[member=36526]Bohdan[/member] - Hmmm, "D Curve" breakers. I'm not familiar with those. I'll have to look into it. Thanks.

 

[Oldwood]

Have you checked the head and motor to see if they spin free?

I would remove the drive belt or belts and spin the head and the motor by hand to ensure they both turn smoothly.

I would also look at the switch, if it is not making clean contact it can cause problems.

Other than that, it could be the start-up capacitor, but I am out of depth troubleshooting that.

Good luck with it.

Gerry

 

[cblanton42]

    In my experience capacitors are fairly robust, I'd lean more toward a dirty or loose connection somewhere in the start circuit especially since it's being used in a very dusty application.  First, I assume you know capacitors can carry a charge so be careful if you expose their connections!!  Anyway, if the motor does spin freely as mentioned then I'd try blowing out inside the motor with a high-pressure air hose in every angle and direction possible for a minute or two, the internal switch actually slides back and forth inside and can get dusty and not make good contact to the start capacitor, (they look like points on an old school car distributor).  If that doesn't work, you can honestly learn more in 5 minutes watching a YouTube video on how to test and check your particular motor than I can type in an hour, that's what I'd recommend.  Good luck, hope it's just dusty!  CB
   

 

[Mortiser]

[member=7143]Oldwood[/member] & [member=18055]cblanton42[/member] , thanks for the suggestions. I'll give those a try. Yes, I am familiar that capacitors can get you if recently charged. I do understand they dissipate with time if not plugged in. But I'll test it and be careful. Thanks again.

 

[tsmi243]

You said the outlet was GFCI- is it possible that the breaker is also GFCI?  We see a lot of false trips with GFCI breakers for some reason.  But not with GFCI outlets. 

 

[Mortiser]

The breaker is not a GFCI breaker.