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By the way, the shock didn't really hurt, just scared the crap out of me and made me instantly pull away
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I finally got my KX3 from Sieg. I haven't yet cleaned all the lube off it and was eager to see what happens when I turn it on so I did and it made a hissing noise which I assume is normal but then I decided to test out the estop and got a small electric shock while touching the casing of the machine. Has this happened to anyone before? Kind of scared to turn it back on. Is there a way to measure a potential shock with a multimeter so I don't have to get zapped during the figuring out process?
By the way, the shock didn't really hurt, just scared the crap out of me and made me instantly pull away
Obviously parts of the machine are ungrounded and should be corrected before using the machine, not only for personal safety but also prevent damage to machine electronics.
Al.
CNC, Mechatronics Integration and Custom Machine Design (Skype Avail).
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Where exactly should i start looking for ungrounded wires? Can I use a multimeter on the casing somehow? Lastly, is the hissing noise normal? Sounds kinda like a coolant pump but I haven't even connected one yet.
Hissing sound could be stepper motors?
Initially use an Ohm meter to measure from all metalic parts of the machine to the ground terminal of the power socket the machine is powered from.
You should have zero ohms, if high resistance then you need to trace the ground wire(s) in the system and discover where the open ground is.
If you get zero ohms then switch the machine on and at the power source, measure AC voltage from the hot or live conductor to the ground conductor, you should get 120v.
If not, then your service ground conductor could be open.
BTW, there have been many instances here of ROC equipment not complying with N.A. electrical code standards and in some cases, very dangerous practices.
Al.
CNC, Mechatronics Integration and Custom Machine Design (Skype Avail).
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Is there normally supposed to be a sound when you turn on a Sieg machine? Yah could be the stepper motor, sounds like its coming from a black box under the x axis motor.
Anyways, I put my multimeter to Ohm's and connected one end to ground and the other end to a screw connected to the base and get 0 ohms. I am using the 220V version. I will try to test the voltage now and see if there are any wires disconnected.
I got the machine connected to my computer and mach 3 running, the axis's seem to move in the jog control window but I am still concerned about the shock and sound. I made a recording of the sound soundscnc.wma Is this hissing sound normal? It seems to change a bit for a second after moving one of the axis.
Haven't touched the case since I got the shock, kind of scared, is there anyway I can test if a shock is there exist with the multimeter instead of my finger?
If you test AC voltage from any part of the frame to the ground conductor, there should be 0 voltage.
You should get to the bottom of it before using the machine.
Al.
CNC, Mechatronics Integration and Custom Machine Design (Skype Avail).
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
It seems to be working fine now, I did the measurements and they were successufl then finally got the guts to touch the machine again (very hard) and no shock anywhere. I think it could have been the plug socket as it may not have been grounded properly via the surge protector so I plugged it directly to the wall for now. Still not sure if that noise is the steppers or not though.
Actually while putting the screws back on the case I got a little buzz when my hair touched the bare metal. Put my finger there and felt a buzz after holding it there a second or so. At least its no longer dangerous but I am now worried about damaging the machine. Should I get an electrician to come in?
I get a small shock even when the machine is off. Could I just ground a screw from the machine case to the ground on the circuit?
Also heres a video of the sound I am getting http://www.youtube.com/watch?v=-sLsR2jZjEs]Video0008 - YouTube
You should not feel a shock when you touch the machine frame or any other parts of your equipment.
All metal items on the machine should be connected directly to earth ground, at a single point The earth ground point is normally the green conductor in the power cord. This green wire should in turn be connected directly to your plant or house ground rod. The only exception to this would be the components that a supplier states must not be grounded. This is very rare and these devices must be insulated and marked as "ungrounded".
Missing, unconnected or poorly installed ground wires can cause portions of the machine to be at the power line potential. Contact with this voltage may cause serious injury or death. Do not operate the equipment unless it is properly grounded.
Take a look at the socket and plug that is powering the machine. Both must be the 3 wire type with the third contact connected to the power supply earth ground. People have been known to cut this terminal off. If that looks and tests OK unplug the machine from the wall and connect the common lead from your multimeter to the ground terminal in the machines control panel. Set the meter on ohms and measure from the terminal to the third contact on the plug. The meter should read zero ohms.
If that is OK, switch your meter to AC volts. Turn on the machine and than plug it back into the wall. With the machine powered, measure from the ground terminal to each metal part on the machine. All should read zero volts. If you read other than zero volts, you have a bad ground. In this case, unplug the machine and look for the missing or bad ground connection.
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