Grizzly Jointer Motor problems

[Dave Rosner]

Hi - I got 200 bd ft of maple delivered last Friday and told the family I was going to be gone all day Saturday and not to expect me around. Then I went into my workshop sat bright and early to get down to business and my jointer just hums and throws the breaker...


Many days later and 2 calls to grizzly tech and here is where I am. I put in a new starter cap today and took apart the centrifugal switch. Tested all the electrical connections and all seems fine. Turned it on and the motor spun up, switch clicked to run and all was good. Then I tried again and very slow turn with a hum - no click to run. Took centrifugal off and the plate with the contacts and tried it again. Same thing - works first time then no good.

When I watch the grizzly video it says to align the switch so the contact just closes. Then push it 1/16th in further. However on my model the switch only goes so far in - but i checked continuity and it was good when I install it.

I’m going to try grizzly again and hope they just send me new parts overnight so i can get to work.

Anyone else come across this?

[Phillip Gregory]

Hi - I got 200 bd ft of maple delivered last Friday and told the family I was going to be gone all day Saturday and not to expect me around. Then I went into my workshop sat bright and early to get down to business and my jointer just hums and throws the breaker...


Many days later and 2 calls to grizzly tech and here is where I am. I put in a new starter cap today and took apart the centrifugal switch. Tested all the electrical connections and all seems fine. Turned it on and the motor spun up, switch clicked to run and all was good. Then I tried again and very slow turn with a hum - no click to run. Took centrifugal off and the plate with the contacts and tried it again. Same thing - works first time then no good.

When I watch the grizzly video it says to align the switch so the contact just closes. Then push it 1/16th in further. However on my model the switch only goes so far in - but i checked continuity and it was good when I install it.

I’m going to try grizzly again and hope they just send me new parts overnight so i can get to work.

Anyone else come across this?

It sounds like the centrifugal switch is not returning to the "resting" position until it has been sitting for a while. The motor type Grizzly uses is the typical centrifugal switch seen on newer Asian motors, where the counterweights raise a collar as they spin up to about 75% of full load speed. The collar that was pressing to hold down a circular contact rises, the bent-metal (and thus springy) contact rises, breaking the circuit that energizes the start circuit and the motor switches to run mode. Once the motor is de-energized, the counterweights slow down and the springs connected to the counterweights are strong enough to pull the counterweights in toward the shaft, lowering the collar and re-engaging the start contact. You should hear a click a second or so before the motor completely stops when the springs pull the counterweights and collar back "in" to the start position. If you do not hear a click on stopping, the centrifugal switch is not re-engaging, and you are going to have a motor that hums and generally does not start. I would de-gunk the counterweight pivots, and if they are not gunky, move the counterweight assembly a fuzz inward (along the shaft towards the motor) to ensure the contact closes when the counterweights decelerate.

You could also be dealing with a circuit that is very marginal in providing power to the jointer. Many 120 volt circuits fit that bill. I did a lot of woodworking with my Dad when growing up and he only ever bought tools that could run on 120 volts, and ran everything on 120 volts even if it was able to run on either 120 or 240 volts. That house has 20 amp circuits with 12 AWG wire for all of the 120 volt circuits and we would routinely trip breakers when running the 1 1/2 hp jointer when face planing or with his 1 hp contractor saw when ripping anything beyond 3/4" thick. He had and still has a 1 1/2 hp air compressor that only starts about half of the time when directly plugged into a receptacle close to the breaker panel. Plugging it into a receptacle farther away from the panel is even more iffy, and an extension cord is a guaranteed no-go. He has 240 volts to the panel and even has a 240 volt 50 amp outlet for his one 240 volt tool, an arc welder, but declines to switch anything to 240 volts due to "complexity."

I learned his lesson and all but one of my stationary tools run on 240 volts so they draw fewer amps and incur less I^2*R voltage losses. The one that runs on 120 volts is a small 8" bench grinder that wears a wire wheel and is a 1/2 hp 120 volt only motor. Everything else is 240 volts. No tool I have had has ever failed to start or has tripped a breaker as a result, and most of my tools are 3+ hp with the largest being 7 1/2 hp.