Motor running slow on Grizzly G0490 Jointer

[David Masters]

The other night, I turned on my Grizzly jointer to put an edge on a board. There was a deep rumble that shouldn't have been there, and when I looked at the belt, it was coming off the lower pulley. Upon further inspection, the lower pulley was missing the key and turning pretty freely on the shaft. I tried to reinsert the key and tighten things down, but the pulley would start to spin off the motor shaft within the first minute after the motor started. Checking the pulley, I found the inner diameter of the pulley was about 1/64th of an inch more than the motor shaft and the aluminum looked like it had worn down. I ordered a new belt, key, and pulley from Grizzly which arrived today.

Installed the new pulley which is much tighter than the old one. Aligned the pulleys, which was a pretty subjective exercise. Grizzly doesn't give you much advice here, just align the pulleys with a ruler. So I stuck a ruler from one pulley to the other and measured from the ruler to the back of the cabinet at both pulleys. Seemed to be pretty good. Tightened the belt to 1/4" deflection as the book suggests. Turned on the jointer and had terrible belt fluttering. Then before I could hit the off switch (which was less than 5 seconds), something went pop and there was a puff of smoke. I checked the alignment on everything and didn't see anything wrong.

Now when I start the jointer, the motor turns at about 1/8th the speed as before. There appears to be some kind of circuit in between the motor and the switch, which is where the pop come from. When I opened the box to the circuit, I found a small blue spring tab that was popped out. You can push it in, but it doesn't stay in place.

286504 286505

Pretty unhappy with myself right now. I figure I messed something up pretty bad, but I'm lost as to what. Grizzly technical support doesn't open until Monday morning, so can't do anything this weekend. Any suggestions on what I might try?

[John McClanahan]

Try pressing the blue tab in firmly. That is the motor overload protector. The tab popping back out is normal. It is set for manual reset. The top part of that unit is the 3 phase contactor.

The overload should have tripped out all phases, so if pushing the blue button doesn't work, don't be too surprised.

John

[Rod Sheridan]

The belt sounds like it\s too tight.

The ruler is to be placed alongside the pulleys like a straight edge to make sure that they are in alignment.

It's not a measuring excercise, it's an alignment excercise with a straight edge (Using the word ruler was a bad choice).

The overload is tripping ( blue button) becaise the motor is drawing too much current.

You may have experienced a failed starting capacitor at the same time (smoke).

Take the belt off and see if the motor starts OK........If not, it probably needs a new starting capacitor.............Regards, Rod.

[Myk Rian]

Belt IS too tight. You should be able to roll it off the pulleys with just a little effort.
Scrap that 1/4" deflection nonsense.

[Bill Space]

I made a device to help me align the pulleys on my G4090X. Simple and easy to make, and worked real well... See photo attached below...


http://www.sawmillcreek.org/attachment.php?attachmentid=251151&d=1358209335&thumb=1

[John R Hoppe]

Your starting capacitor has failed. Same thing happened to my 0490X, I called Grizzly and had a new replacement in 2 days. On the belt, even if it were too tight, the motor would still spin at full RPM.

[glenn bradley]

+1 on start cap. Temco (http://www.temcoindustrialpower.com/search.html?category=AC_Electric_Motor_Start_Capac itors)is a fraction of the Grizzly price for better quality. They are super helpful over the phone if required. No affiliation, just a satisfied customer.

[Lee Schierer]

I agree with the others on the start capacitor going out. However, I would also check to insure that the cutter head rotates freely. If you had flutter in your belt, the belt wasn't too tight. You may have a bad bearing or something rubbing on the cutter head.

[Gary Salisbury]

From my experience, some electric motors have a "start" winding (which runs slower with more torque to get the machine under load up to speed) then switch over to a "run" winding" (which runs at full speed). Those that do have a capacitor and relay to start out on the lower speed start winding then switch over to the run winding. I have seen a bad capacitor or relay fail to transfer to the run winding and keep a motor on the start winding running slower.

I don't know if this is your problem but it is something you could check out. Just a suggestion from someone who went through US Navy Electricians School many years ago.

Gary Salisbury
Sunny Blossom Valley, Kalifornia

[David Masters]

Thanks to all that responded. Your diagnosis and suggestions were right on the mark. I wasn't able to get back to the jointer until this morning due to plans my wife didn't tell me I had, and taxes.

I loosened the belt considerably to the tension suggested by Myk. I started the motor and it ran much faster, but still not to the point I remember.

Called Grizzly support this morning. As John mentioned, the blue tab position in the picture is normal. Pushing the tab in does a reset, but then springs back into the position shown in the picture. The technician had me look at the large capacitor on the motor, and it was blown (oily inside the casing and around the capacitor). Ordered a new one for $15 + shipping. It should be here at the end of the week.

I'm glad my boneheadedness isn't going to cost me a lot of money. Next time I'll ask questions before I blow things up.

Dave

[Brian J Jenkins]

Don't feel bad, its part of learning :)

[CPeter James]

Does this motor have one capacitor or two. Some motors also have a run capacitor and if that fails, they will run slow and also trip the overload. If the start capacitor fails, usually the motor won't start at all, but just buzzes. I have Grizzly motors with two capacitors and had a problem with the run capacitor connection coming off. The condition was just as you describe. On the same motor the start winding contacts were not opening on time and so the motor would stay in the start condition which would lower the rpms and run rough.

CPeter

[David Masters]

The parts breakdown for the jointer shows two, but appears to be only one on my machine.

Dave

[David Masters]

Postscript: Easter, taxes, new granddaughter, and Spring got in the way of fixing my problem. I finally got to it a couple weeks ago. My thanks to all who responded. Special thanks to Grizzly technical support who were wonderfully patient with me.

I'm certain that most who follow this forum already know this, but for Newb's like me, I'll share what I learned.

When I installed the motor start capacitor, it failed within seconds after starting the motor.

What the motor start capacitor does is provide a short initial jolt to the motor to offset any magnetic alignment that might occur after the motor spins down. The capacitor itself cannot stand to have power applied to it more than a couple of seconds before it overheats and fails. To prevent this from happening, there are a set of points secured around the motor shaft (other side of the shaft from the pulley) that cut out power to the capacitor as the motor spins up. The way this works is that a centrifugal switch secured to the shaft keeps the points closed when the motor is at rest. As the shaft rotates, the centrifugal switch retracts which causes the points to open, thereby cutting power to the motor start capacitor. In my case, the points were burned and needed to be replaced.

To fix the problem, I had to order the following from Grizzly:

(1) PCP001 CONTACT PLT-TUNGSTEN 5HP OR LESS
(1) PC200A S CAPACITOR 200M 250V 1-3/8 X 2-3/4

There is a document that Grizzly sent me that outlined how to set the centrifugal switch, which in short was to push the switch on the shaft until the points just touch, then push the switch into the contact ring another 1/8" before securing it on the shaft. Grizzly has a document they can send to your email called "CENTRUFUGAL SWITCH REPLACEMENT/ADJUSTMENT(Motor Fan-End Locations) INSTRUCTIONS" that gives you very detailed instruction.

As ugly as it sounds to crack into the motor, it wasn't bad at all. You have to remove three screws to remove the motor cover, then remove the fan, then the centrifugal switch and then the contact points collar. You don't have to remove the motor from the Jointer to accomplish any of this. What I did was to put a mark on the shaft at the point where the centrifugal switch at the point the contact point just closed, then took the centrifugal switch off the shaft and measured an additional 1/8" from the mark toward the contact point collar. Then I pushed the switch to the second mark on the shaft and tightened it down. The motor fired right up.

Hope this helps.

Dave

[scott vroom]

Any idea what caused the initial problem?

[David Masters]

Not really. My guess is that I did something to knock the switch or the points out of alignment just enough to cause the points to arc when they should have opened. Maybe it was having the belt too tight initially or happened when I tapped the new pulley onto the shaft.

Dave

[Nick Spencer-Berger]

I'll second what David found out. I had the exact same symptoms on my G0490X and I tested the capacitor, but it seemed okay. After properly aligning the centrifugal switch, it started right up. I am guessing when I was attempting to align and tension the belt, I did something to get the switch out of alignment.