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Ground Wire in MARK V

Posted: Mon Mar 02, 2009 10:25 am
by eartigas
Hi:

I just bought a MARK V (circa 1981) and I am cleaning and upgrading it. What I noticed is that the electric cable entering the headstock has the black and white wires connected but the green wire is cut short and connected nowhere.

I gather that this is not right.

Questions:

Where is the green cable supposed to be connected in the headstock?

Is there any other grounding connection that I can't see?

I did not drop the motor so I havent's seen it all inside.

Thanks

Posted: Mon Mar 02, 2009 10:36 am
by beeg
Welcome to the SS forum eartigas.
My ground wire is attached to the motor, on top there's a lug for it on the spindle end of the motor.

Posted: Mon Mar 02, 2009 3:01 pm
by dusty
beeg wrote:Welcome to the SS forum eartigas.
My ground wire is attached to the motor, on top there's a lug for it on the spindle end of the motor.
Yes, the green wire should be connected to the motor housing, as beeg has said. However, mine is connected to a mounting screw on the other end of the motor.

It can be connected to anyone of the screws in the motor casing and be just as effective. Just make certain that you don't have a painted surface acting as an insulator. I use a star washer so that the teeth will bite through any paint that might otherwise be an insulator.

Ground wire: thanks for the help

Posted: Tue Mar 03, 2009 2:20 pm
by eartigas
Thanks for the information that confirmed my suspicion. Somehow the wire got cut but it still easy to reconnect to a good ground point.

Regards

Posted: Tue Mar 10, 2009 8:55 am
by robinson46176
I just wanted to mention that often folks don't realize the importance of maintaining the ground and they chop the ground prong off of the plug or use a grounding adapter without grounding the adapter (I have been guilty). What they don't think about is that cutting the prong off is worse than the machine having never been grounded. Think about it, with a ground wire but no prong if the insulation inside of the power cord breaks down not only can you have the usual sparks and fire risk but you now have a direct path up the green wire to the shell of the machine... It can still go to ground, through you... In that case about the only possible protection from shock is if you happen to be plugged in to a GFI outlet. People who chop off ground plugs rarely have GFI outlets. This isn't just Shopsmith stuff. I have bought a lot of Shopsmiths with the ground prong cut off but the same applies to power hand saws,electric drills etc.
Plastic cases and double insulated tools now with 2 prong plugs has helped a lot but there are still a lot of the old ones out there. I hit a "lot" of yard sales and see tool after tool with the ground prong cut off.

Posted: Tue Mar 10, 2009 1:42 pm
by charlese
Remember the "Good Ol' Days" when if we got a shock from a lamp, or an electric driven machine, we just pulled the two prong plug from the outlet - turned it over and re-inserted it?

Actually, when an instructor in Army electronic training, we used to teach this method.

Now days, thanks to the varying size of the prongs, at least the neutral side of the cord is always connected to the neutral side of the outlet. (assuming that one does not have antique outlets) The only way we would get a shock from a tool is if a hot wire came loose and in contact with a ground.

Posted: Wed Mar 11, 2009 12:26 am
by JPG
Back in the really old days things were different. It is in the middle years that things were dicey.

Since day one permanent wiring receptacles HAVE been polarized! Even the original 'edison plug' (think lamp base with a cord coming out where the glass bulb is normally) was polarized(shell neutral, hot down inside). The 2 prong receptacles had a hot and a neutral side(wide/narrow) even then.

At some time (40's?) the two prong PLUGS(non polarized) appeared. Extension cords had female non-polarized ends.

All this time the wire WAS polarized(color/ribbed rubber,plastic) as it is today.

Eventually grounding(3 prong) receptacles were 'thought of' and houses have since been wired with the familiar 3 prong recepracles which still has a wider neutral blade.

And finally almost all current devices have the polarized 2 prong plugs except double insulated devices which MAY not.

The problem we got into was the almost universal use of NON-POLARIZED plugs on just about everything in the middle of the last century. These really posed a hazard with 'ac-dc' radios and TV's. Invariably the manufacturers would put a capacitor between one side of the linecord and the chassis. This created the reverse the plug scenario.

Then along came GROUND FAULT CIRCUIT INTERRUPTERS which invariably would trip when one of them was plugged into them.

History lessen END!:)