Tommy
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Post by Tommy on Aug 28, 2018 14:59:02 GMT -5
It's more of a statement than a question but I'm still puzzled how it's happening. When I'm cabbing barefoot while standing on rubber anti-fatigue mats as I like to do, when my hand comes in contact with the metal pan I get a mild shock at the point of contact. The thing is, the motors on both of my grinding units are independently mounted on wood and the only contact is through the rubber v-belt.
I understand electricity pretty good, I understand grounding, and I installed the back wall ciruit that runs directly from the main circuit box, down the length of my work bench wall with four outlets. Yes it is grounded and phased properly and the outlet my grinders are plugged in at is GFI.
So then this has to be an electrical field generated by the spinning pulley/shaft/wheels etc. right?
Anyone experienced this before?
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fishnpinball
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Post by fishnpinball on Aug 28, 2018 15:15:51 GMT -5
I would guess you are building up a static charge. If it is just one shot and gone for s bit that is it.
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Tommy
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Post by Tommy on Aug 28, 2018 16:21:11 GMT -5
I would guess you are building up a static charge. If it is just one shot and gone for s bit that is it. It is not a one-and-done. The shock remains as long as I leave my finger in contact with the bottom of the pan. It's actually a powerful little shock to the point where I can't leave my hand there for more than a couple of seconds or it actually hurts. To take it one step further I just noticed that my finger does not need to contact the bottom of the pan but if there is a continuous stream of water coming off of my finger the shock is transferred up the water to my finger. Very strange...
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Don
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Post by Don on Aug 28, 2018 16:22:52 GMT -5
It's more of a statement than a question but I'm still puzzled how it's happening. When I'm cabbing barefoot while standing on rubber anti-fatigue mats as I like to do, when my hand comes in contact with the metal pan I get a mild shock at the point of contact. The thing is, the motors on both of my grinding units are independently mounted on wood and the only contact is through the rubber v-belt. I understand electricity pretty good, I understand grounding, and I installed the back wall ciruit that runs directly from the main circuit box, down the length of my work bench wall with four outlets. Yes it is grounded and phased properly and the outlet my grinders are plugged in at is GFI. So then this has to be an electrical field generated by the spinning pulley/shaft/wheels etc. right? Anyone experienced this before? 1dave
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Wooferhound
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Post by Wooferhound on Aug 28, 2018 16:34:12 GMT -5
Possibly a Piezo electric effect from the rock ? Could it be some kind of static generator ?
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Post by stardiamond on Aug 28, 2018 16:40:10 GMT -5
You probably need input from other barefoot cabbers. Was this a recent one time issue or an ongoing problem? I don't know the difference between standing on a rubber mat or wearing rubber sole shoes. My pans are all plastic.
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Post by rockjunquie on Aug 28, 2018 16:49:54 GMT -5
Ouch! Hope you figure it out- seems like it could be dangerous.
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Post by MsAli on Aug 28, 2018 17:14:03 GMT -5
After my last incident, I dont go barefoot anymore. Not sure it would of made a difference if I had shoes on
Does it still happen when you have shoes on?
Are you positive there isnt a little piece of bare wire somewhere?
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Post by 1dave on Aug 28, 2018 18:33:56 GMT -5
Quartz is piezoelectric. Pressing it against a wheel can generate up to 30 volts.
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Post by vegasjames on Aug 28, 2018 20:23:35 GMT -5
A static discharge would not remain so I would suspect:
1. "Leaking" of electricity from a microcrack in the electrical wire.
2. Or more likely the dust on the machine is conductive and is transferring the electricity from the motor to the water tray.
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Post by parfive on Aug 28, 2018 20:57:18 GMT -5
Is your “anti-fatigue mat” also conductive or anti-static?
What kind of floor is it on? Concrete?
Move the mat and stand on the floor barefoot. What now?
Shoes on the floor, shoes on the mat. What now?
Got a good voltmeter/multimeter? Fart around with that.
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Tommy
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Post by Tommy on Aug 28, 2018 21:36:56 GMT -5
Possibly a Piezo electric effect from the rock ? Could it be some kind of static generator ? I've been experimenting and playing with it all day and I've learned a few things. First of all the rock doesn't need to be involved - it happens even when I'm not actively grinding. As long as the wheels are spinning and water is flowing and I can touch anywhere on the metal housings or pans of either machine and I get the current. If I touch with the pad of my index finger I feel nothing - if I touch with the tender skin on the side of my little finger (as is usually the case when I'm grinding) I get sharp and prolonged current until I have to pull my finger away. I just now held the side of my pinky to the metal and turned the switch on the the current turned on instantly with the switch. The two machines are not touching in any way - 4 inches of air separate them. Water is delivered to both machines via plastic hose from the same submerged aquarium pump in my recirculation tank.
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AzRockGeek
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Post by AzRockGeek on Aug 28, 2018 21:41:44 GMT -5
Do you get shocked if the wheels are turning and the water pump is unplugged?
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Tommy
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Post by Tommy on Aug 28, 2018 22:11:11 GMT -5
Do you get shocked if the wheels are turning and the water pump is unplugged? OK, yeah... pump plugged in current - pump unplugged current stops. Weird... OK so pump plugged in = current yes but the valve was off so no water was flowing. This almost has to mean that the current is coming from local where the pump is plugged into the outlet near the motor. Still doesn't explain how the current is getting to the machine - it almost has to be coming through the belt.
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AzRockGeek
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Post by AzRockGeek on Aug 28, 2018 22:26:36 GMT -5
Water is a conductor, you could have a minor short in the pump and the electricity is traveling up the water lines and shorting out from the water valve to the grinder housing. Is the valve brass? If so, it could short out to a metal housing or anything that is wet.
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AzRockGeek
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Post by AzRockGeek on Aug 28, 2018 22:30:06 GMT -5
I highly doubt that the current is traveling through the v-belts. If you have a multi-meter try measuring the voltage from ground to the water valve with the pump on and grinder off.
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Post by parfive on Aug 28, 2018 22:34:09 GMT -5
Doesn’t say much for that GFI at your workbench, assuming the submerged pump is also fed off the GFI.
If “It's actually a powerful little shock to the point where I can't leave my hand there for more than a couple of seconds or it actually hurts,” it should've tripped the GFI.
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Tommy
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Post by Tommy on Aug 28, 2018 22:52:20 GMT -5
Water is a conductor, you could have a minor short in the pump and the electricity is traveling up the water lines and shorting out from the water valve to the grinder housing. Is the valve brass? If so, it could short out to a metal housing or anything that is wet. Yes it is brass. The thing though is there is a reservoir in between - the water is pumped up out of an aquarium under the work bench and it goes into a PVC pipe with lines dropped off of it and a valve on the return which forces water to the units when closed. I noticed a while ago when I was unplugging the pump that it was suspiciously close to the belt - maybe it rubbed on the belt at one point and has a break in it. I'll give the whole thing a closer inspection tomorrow. I'm excited though - we've narrowed it down greatly, thanks Tim!
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Post by Peruano on Aug 29, 2018 7:15:35 GMT -5
Its not out of the realm of possibilities that your belt is conductive. Yes they used to be made of rubber, but now may have reinforcing fibers and who knows what. I'd wear shoes.
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Post by rockpickerforever on Aug 29, 2018 9:25:42 GMT -5
Mrrockpicker used to work with a guy in charge of putting textured finishes on metal projects. Whenever he used an electric tool (small body-grinder type tool), he kept getting shocks. No water was involved, only static buildup.
The solution was to ground himself, by attaching a light chain to his pants (contacted skin at waist?) that touched the floor. Problem solved.
I don't think he ever had the problem of getting shocked when using a pneumatic grinder.
ETA - Or, you could just wear shoes! lol
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