Electricity Problem with Kalamazoo 2X48 belt sander

[sunpeople]

I bought a used Kalamazoo 2X48 belt sander (120 volt) a few months back, its a Craigs list find for 90 bucks! i could not pass it up. The problem i am having with it is every time i use it i get shocked by it. Just to let everyone know it has a three prong plug and the outlet is grounded. Now i have two other belt sanders one is a 1X42 Kalamazoo 120 volt and the other is a Grizzly 6X48 240 volt.

Now when i run the other belt sanders i don't get a shock from them and the 1X42 is run off of the same circuit as the 2X48 so whats going on here? Could this be a build up of static electricity? If it is why does it not happen on the other sanders? and if it is a build up of static how do i stop it?

I just want to make sure my problem is clear to everyone, i only get a shock when i touch the case (any metal part of the sander for that fact) after the sander has been running or after i have sanded something on it, most of the time its when i go to turn it off and touch the switch. I have tried running it and sanding an item while i held my hand on the case and after i was done i would not get a shock when i went to turn it off. So based on the info i have given here, do i need to run an extra ground wire of some kind? If i do were do i hook it up at? From what to what?

Any help you can give would be great. This has made me start to think maybe i didn't get such a great deal on this sander if it keeps shocking me.

[MichaelP]

First, I'd check if the case is grounded. If you're sure that the outlet is indeed grounded and not just looks like it is, then all you need is to make sure that the metal case of the saw is grounded too. Unplug the machine and use a continuity tester or, better, an ohmmeter between the case of the saw and the ground pin of its plug. Normally, they should be connected to make the machine safer. Use your ohmmeter in the lower range (Ohms): of the items are connected, it'll show a very low resistance.

If the case is grounded as it should be, then the probable cause is the statics accumulated on your body.

While you're at this, you may want to check resistance between the case and either of the other two pins of the plug (not the ground pin). Use the meter in midrange (kOhm) and high range (megOhm). There should be no connection between either of the pins and the case (meter shouldn't register any changes after you connect its leads).

[Jake_SS]

Do not use

Firstly DO NOT use it at all, it may be full of grinding dust, or something touching where it should not be which is causing the problem, you would need an Insulation Resistance tester to test it properly not an ohmeter, forget about static from your body this is more serious, if you dont know much about this sort of thing take it to someone that does, do you have a RCD (residual current device) connected ?

[MichaelP]

RCD (residual current device)

A.k.a. GFI (or GFCI) outlet.

[CornHusker]

Static electric shock...

Making sure I understand what you have ask: You have a sander that you are getting shocked when you touch it. But ONLY after it has been running? And you are NOT getting shocked if you maintain contact with the case while you are sanding. Correct?

It appears you are receiving and electro-static shock. NOT a shock directly from the plug voltage. You have a sander with a belt moving around and around building up a static charge and the device used to drain off this ‘charge’ is malfunctioning. (Similar to walking across a carpet and touching someone?) This is not dangerous, however irritating it might be.

There is a grounding strap of some kind built into the sander that ‘drains’ the static charge away from the belt and to ground. It is not functioning correctly…. Take the sander apart or at least remove the belt and examine the area closely. Perhaps examine the other sander of the same make and find out where this grounding strap is located. Fix it and off you go…. No more shocks.

[MichaelP]

If the case is grounded, touching it will result in static discharge only if the source of the charge is you body.

If the case (or whatever else you touch) is not grounded then the statics accumulated by the sander will certainly be able to produce the discharge through your body.

[Jake_SS]

Risk

Do you think it is worth the risk without properly testing it !!!!!!!!
Sure open it up and clean it out, then take it to someone that has the proper test gear, would take them about 1 minute to test it for you. Would you stick your finger in a socket to see if the switch is off! I think not, this is the same deal.

[sunpeople]

Thank you to everyone that has taking the time to try and help me find an answer to my problem. First to MichaelP i will take my Fluke meter and test my sander per your post and see what readings i get on my meter.

Next to Jake_SS i will use my air hose and blow out the inside of the sander to remove as much dust as i can and to answer your other question NO its not on a GFCI its on a 20 amp braker.

And now on to CornHusker, yes you understand the problem right , i tend to think that it must be static too, because as i have said if i hold my hand on the sander with it running i get "NO" shock, its just after i have been sanding an item and go to turn it off that i get a shock, so i will do as you said and look and see if it has some type of static control device that is broken and needs to be fixed.

I will post my meter readings here after i test it and also tell you if i find any broken parts. Thanks again to everyone that has tried to help me with this problem, you guys are great.

[sunpeople]

This is an update for MichealP,i checked the sander with the Fluke meter per what you said and the ground pin of the plug is hooked up and working. I checked to see if i got a reading between the ground pin and the body of the sander and it checked as good, then i checked both of the other prongs of the plug, to the case of the sander and "did not " get any ohm reading at all so they check out okay.

Next this is for Cornhusker i pulled off the covers on both this sander and my smaller 1X42 sander to see if i could find some type of static ground on either one of them like you said to do and i could find nothing that even looks like some type of a ground.

This next part is for Jake_SS i took the air hose and after i removed the covers from the sander and blew out the inside of the sander, but this sander is nothing more than a TEFC motor with a wheel mounted on the output shaft that runs the belt so there is not a whole lot to blow out. After i did this i tryed it and it still has the same problem.

Cornhusker maybe you could give me some ideas to try. maybe you could tell me were to put a ground wire to bleed of this static charge that is building up on the sander when i am running it

Now after doing all of this i still have the same problem so does anybody else have any other ideas how to fix this "Shocking Problem". I am sure that there is a simple answer to this problem but i am just not seeing it, i am sure someone here like MichealP , Jake_SS or Cornhusker will solve it for me because right now i am at a lost as what to do next, so please give me some more ideas to try.

[Wyoming]

Try running a short section of bare stranded wire with a light spring action against your sander's pulley belt with the other end hooked to something that is grounded...water pipe, ground rod, whatever. Your problem sounds like static electricity and the belt or the motor shaft probably are rubbing something enough to create it. Start with the belt and see if that doesn't get rid of the problem.

[Monte55]

Is the sander on a metal stand or wood bench top. I've never heard of this happening with a sander..(I have two on metal stands on concrete)and they don't do this. Now my shop vacs with plastic hoses and on plastic wheels will shock me if I do a lot of dry sawdust and the air is dry in my shop. If you are
have a concrete floor you might connect a ground wire to the case and to a metal piece on the floor or you can get a wrist ground strap like computer guys use and ground yourself to the sander while using but that would be a pita. If you don't get it fixed, I'll give you a dollar for the sander

[bandsawguy]

I would try to attach a wire to the case and the other end to a ground like a pipe then see if it still happens.

[Willy Victor]

How about standing on a rubber mat.


Willy

[sunpeople]

I though i would update everyone who has tried to help me with my problem. I wanted to take this time to answer some questions that were asked of me. First the sander is mounted on a wood bench, for that fact all three of my sanders are all on the same wood bench, next when i use it to sand something i stand on a rubber mat that runs the whole way in front of the bench that the sander are on so i am not standing on a bare concrete floor.

What i tried today to fix the problem was what Bandsawguy said to try, I ran a #12 wire from one of the screw heads on the sander case to the EMT conduit that i have all of my electrical power running in to power all of my shop tools, the bad news is this did not solve the problem. Just in case someone asks the conduit in the shop is all grounded to a copper rod that i sunk 8 feet in the ground outside the shop.

I am going to try what Wyoming said to try, i will see if i can set something up this afternoon and see if that works. By the way Monte55 i am not to the point yet, of wanting to sell the sander, but thanks for your offer of 5 bucks. If anybody else has any suggestions please offer up your ideas and i will give them a try.

[bandsawguy]

Try making a hat out of aluminum foil and wear that while sanding.

Other than that I am out of ideas.