I have an old grinder on a stand. Very heavy duty but 110 volt only.
Whenever i use the thing, if I touch something that is grounded to earth or if I were to be barefoot on the concrete and touch the grinder while running, it will give me a real good shock.
How should I address this? Can I simply ground the body to stop the problem?
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I refuse to accept that there are limitations to what we can accomplish. Pete Draganic
Take life as a test and shoot for a better score each day. Matt Garcia
Replies
You need to find out why it is hot. Could be the hot wire is shorted to the frame, or the motor could be bad. Just grounding it may simply trip a breaker.
From your description Pete, I'd say grounding will definately trip the breaker. Since it's working otherwise, I wonder if it is simply a matter of needing a polarized plug as well as grounding. I'd take a coltage reading from chassis to ground, then try it again with the plug reversed. If in fact that solves the voltage issue, then you can wire a polarized plug and ground the machine, or a whole new cord with an integral ground connected to the chassis...
HTH
PaulB
http://www.makeabettertomorrow.com
http://www.finecontracting.com
The outlets in my garage are not grounded so I would have to ground it independently if that would remedy the situation.So you think it may be simply wired in reverse? dumb question but would that also make it run the opposite direction? It currently runs in the correct direction, being downward. This motor has a shaft through both ends and a wire wheel on one end and stone on the other.Probably over 50 years old.I will check it out later and see what I come up with.It only shorts when running, i think.
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I refuse to accept that there are limitations to what we can accomplish. Pete Draganic
Take life as a test and shoot for a better score each day. Matt Garcia
Wouldn't affect the rotational direction but could very well cause the problem you're having if it's a very old design. Let me know what you find...
PaulB
http://www.makeabettertomorrow.com
http://www.finecontracting.com
sure, thanks
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I refuse to accept that there are limitations to what we can accomplish. Pete Draganic
Take life as a test and shoot for a better score each day. Matt Garcia
So you think it may be simply wired in reverse?
No
dumb question but would that also make it run the opposite direction?
No
It currently runs in the correct direction, being downward. This motor has a shaft through both ends and a wire wheel on one end and stone on the other.
It has to have a leak to ground, either in the switch, the wiring, or the motor. Take it to a repair shop, and see what they say. Or open ot your self and check for bare wires. It should be fixed
I see, I misunderstood you originally.
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I refuse to accept that there are limitations to what we can accomplish. Pete Draganic
Take life as a test and shoot for a better score each day. Matt Garcia
Pete... It may in fact have a "leak" to ground, but it may not. Did you try reversing the plug? Or was it already polarized?PaulB
http://www.makeabettertomorrow.com
http://www.finecontracting.com
I disagree that is HAS to have a leak. It might but it's also very possible that it needs a polarized plug. In fact, the reason for polarized plugs was that when I first started fiddling with electronics as a kid they made quite a few devices that had 'hot chassis" which would do exactly what Pete's describing. He MAY have leakage but then again, he may not... simple test to find out.PaulB
http://www.makeabettertomorrow.com
http://www.finecontracting.com
I've never seen a power tool with a hot chassis, and I spent a portion of my life as a power tool repairer. Your hot chassis stuff, was that line voltage, or transformed down? I have a feeling that unless it dates to the '20's, it was a lower voltage.
Line voltage... quite common in the 60s and early 70s as I recall. Used to see it allllll the time in TVs and radios. They relied on wood or plastic cabinets and knobs to protect the users. Don't have to tell you what happened when a knob fell off...PaulB
http://www.makeabettertomorrow.com
http://www.finecontracting.com
Whenever i use the thing, if I touch something that is grounded to earth or if I were to be barefoot on the concrete and touch the grinder while running, it will give me a real good shock
What the hell are you doing in the shop barefoot?
Joe H
Grinding those nasty toenails I'd guess.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Grinding those nasty toenails I'd guess
Belt sanders are great for getting rid of those pesky nails.
Joe H
What the hell are you doing in the shop barefoot?
'Cause he looks funny wearing shoes when he's nude. On second thought, maybe it's not the shoes.............
it's the knee socks.http://www.quittintime.com/ View Image
Take it outside, set it on the grass.
;-)
Take the cord connection apart and you will find your short there, more than likely.
Not much room in those old motors and over the years the heat and vibration have lossened the wires at the terminals or worn a thin spot in the insulation. Find and fix whit a new cord with a gound wire. Bond the ground to the chassie at the cord onnection or cover plate screw.
Add a grounded recepticle wher you plug it in and use a ground wire bonded to the metal box.
And stop runnin that thing barefoot !
Steel toe boots, leather chaps, gloves and a full face shield and a medic alert bracelet are recommended attire :)
Wait- isn't this the same guy who welds in Crocs?Just askin'Steve
Yep.
He lives life on the edge.
man, don't you guys forget anything. You're as bad as my wife.
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I refuse to accept that there are limitations to what we can accomplish. Pete Draganic
Take life as a test and shoot for a better score each day. Matt Garcia
During batting practice one day, I hit a hard one-hopper through the gap into Right.
Unfortunately, the grounds crew were out on the tractors, mowing the outfield, and the ball got chewed up.
Sorry, I can’t help you much with your current problem.
But I can definitely tell you how to grind a grounder.
AitchKay
This is not normal and it has nothing to do with polarized plugs. You have a wire making contact with the motor case or stand. Common locations are where the feed wires go through the hole in the case, in the motor junction box, and in the starter or switch. I don't know how old is "old", but the rubber insulation on machines from the 40s and sometimes later gets crispy with age and breaks. Handle it gingerly, replace any old wire you can, and use shrink tube where you can't.
Most stationary tools before the 60s were wired without grounds. This really isn't acceptable today and you should rewire with a grounded plug to a ground wire that terminates solidly to the motor case. I like to ground at the switch also. If you're using your garage as a workshop and it doesn't have grounded outlets, it's probably time to fix that too.
Pete
Edited 4/8/2009 7:23 pm ET by PeteBradley