Shocking problem with belt grinder

G

G George

New Member
I have been grinding a few blades, and have put a few together, this is more a hobby than a business for me.
I have a Grizzly 2x72 belt grinder.
I replaced the platen recently with a piece of pyro ceramic glass, that i bought at a local wood stove dealer,
i love the surface, but now i get the (you know what) shocked out of me.
The arcs come from the platen steel plate across through my gloves and hand.
Worse than HEI ignition on cars that I've worked on.
I took the belt off and ran the motor, no shock. Put the belt on and zap.
My electric system has a ground installed, and i am on a 20 amp breaker, with grounded outlets.

Has this happened to anyone else, and how do i fix the problem?
What is the problem, is the glass generating the field, static,... I'm stumped.

Thanks for your input...George
 
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Yep, thats static electricity. The lower the humidity the worse it will be. You need to find some way to ground yourself to the grinder.
 
I've tried lots of ideas about grounding myself or the grinder - (some of them dangerous), but the only thing I found that woked was a humidifier in the shop.
 
Mine does that during the winter months. Just keep it warm in there and maybe a humidifier to balance out the humidity levels.
 
I use something like this during drying months but I've modified mine with a quick disconnect that has a 2lb rating so that if ever it gets caught, it just pops off.

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I use a length of wire with 2 aligator clips, one to the grinder and the other to the cuff(wrist) of my shirt or hoody. Make sure the clip is touching your skin and your good to go.


Peter
 
Gentlemen; thank you very much!
I thought about grounding the grinder, never thought of grounding myself to the grinder.
Unfortunately my shop is a carport, and is open in front and top half of the side.

Thanks to all, have a great day!

George
 
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Don't ground yourself to a motor. You can kill yourself that way. Stat wrist bands are for electronics work on non-powered electronics.
Spray laundry type anti-static spray on the inside of belts and on your platen and grinder and it will be greatly reduced. The static is worse in the winter but the static just about eliminates it.
 
BossDog said:
Don't ground yourself to a motor. You can kill yourself that way. Stat wrist bands are for electronics work on non-powered electronics.
Spray laundry type anti-static spray on the inside of belts and on your platen and grinder and it will be greatly reduced. The static is worse in the winter but the static just about eliminates it.
Click to expand...

You have a very good point there, Tracy. I feel a bit "short bus," right now for not thinking it through. I've been using the wrist band for a while now and it never dawned on me. The spray sounds a whole lot less deadly.
 
BossDog said:
Don't ground yourself to a motor. You can kill yourself that way. Stat wrist bands are for electronics work on non-powered electronics.
Spray laundry type anti-static spray on the inside of belts and on your platen and grinder and it will be greatly reduced. The static is worse in the winter but the static just about eliminates it.
Click to expand...

Very good point Tracy. Besides that, the shock in this case doesn't even come from the motor. It comes from friction of the belt.

That being said, EVERYBODY that uses high amperage tools needs to purchas an outlet tester and make sure that all of the outlets in their shop are properly grounded.

I did a test on the outlets in my garage after feeling a shock from my metal work table that my grinder sits on. At first I wrote it off as static discharge, but after checking grounds with an outlet tester, I found that half of the outlets in my garage weren't even grounded!
Turns out that whoever wired my garage was relying on continuity from the outlet mounting flanges to the metal boxes for ground. They just cut the ground wires off. Now this is acceptable practice if you're using conduit or metal clad cable with continuity all the way to the breaker panel, BUT (and this is a big BUT) if the cladding or conduit is compromised or a connector comes loose, OR if the flanges oxidize (or if they don't remove those little plastic tabs from the mounting screws), then your ground is compromised and basically doesn't exist. It's kind of the lazy man's way of wiring outlets and switches, but it happens all the time.

Think about it... Your shop floor is usually made of concrete, and is usually wet from your dipping bucket or otherwise. There are fewer better mediums to maximize path to ground then wet concrete. If your motor faults to ground, you now potentially have 110 to 220VAC and up to 15-20amps of current coursing through your body. If it crosses your heart, that's all she wrote. In industry, 50V is considered potentially lethal, and IIRC, it only takes about 100mA to kill somebody. A 10amp breaker is 100x that amount.

Double check your grounds people. Outlet testers are dirt cheap, and availabe EVERYWHERE.
 
By the way... on a related "electrical" note:

NEVER USE THE QUICK CONNECTIONS ON THE BACK OF SWITCHES AND OUTLETS.
For those of you who are unfamiliar with what I'm talking about, there are two ways to wire most modern 110VAC switches and outlets.

1) Screw terminals, normally found on the sides and bottom portion of the outlet or switch

2) "quick connectors" or "push terminals" on the back of the outlet/switch. These are the little round holes on the back of the outlets that you push a length of stripped wire into, and a spring (or spring loaded tab) inside the hole catchs the wire and makes the connection.

These things are just about worthless and out to be outlawed by the underwriters labratory. I can't tell you how many outlets I've had to replace or rewire because these connections come loose and the wires pull out.
Not only is it a very small tab that is even holding the wire, but if they oxidize, the connections loosen. If the wires get moved at all (happens a lot from a dead short or power surge) the connections can loosen or fail. If the wires get hot or the outlet gets hot, the connections can loosen or fail. It's not really even a matter of IF they will fail, but WHEN.

A loose connection can cause outlets, tools, or other components to overheat, and even catch fire under the right circumstances. Other hazards or potential configurations are too lengthy to mention here, but the point is, USE THE SCREWS.

The quick connections are for lazy electricians and people who just don't know any better, and they're much more trouble than the 45 seconds they save on wiring an outlet.
 
The anti-static spray works from what I've been told. My Wife uses dryer sheets and I just grab one of those and let it rub on the back of the belts. It works for quite a while and then I'll have to do it again. Sure beats getting zapped while grinding. Some of those shocks pack a pretty good wallop!
 
BossDog said:
Don't ground yourself to a motor. You can kill yourself that way. Stat wrist bands are for electronics work on non-powered electronics.
Spray laundry type anti-static spray on the inside of belts and on your platen and grinder and it will be greatly reduced. The static is worse in the winter but the static just about eliminates it.
Click to expand...

Is there any other type of platen I can use on my Grizzly, so this doesn't happen to me ? Haven't had the problem with the stock platen, and it seems to be wearing out fast.
What would you suggest ?
 
My wife is picking up some anti-static spray for me today.
As posted earlier, i had checked my outlets with the tester to see if it was wired correctly, checked the machine without a belt on it, re- checked my breaker box, and the ground wire to see if it had gotten loose, everything is good.
The anti- static spray will fix the problem, and everyone who replied has my thanks!

Happy Thanksgiving to all the knife dogs!
George
 
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