I’ve got an older Taiwanese bench model drill press. I’ve used it fine for years, but last week while I was starting to set it up I got a mild shock when I touched the column. I unplugged it and did the obvious visual inspection for a frayed wire anywhere. Finding none, I got out the multimeter, plugged the thing back in and tested the machine. Sure enough there is about 8 volts running through all the metal parts on the machine. After unplugging it I took the switch plate off and looked at all the wires running inside the machine looking for any frayed or loose wires. I took the cover off the back of the motor and checked in there, too. But I have found nothing that would indicate why there is that current on the machine. So I’m at a loss to know what to do next. I’ve exhausted the extent of my knowledge of how to fix this problem. Anybody got any other suggestions?
Thanks in advance-
Ralf
Replies
Start by opening the box around the switch. Next, to to the starting capacitor(s) and check for dents and bulges. If nothing is apparent, you may have a shorted field winding in the motor. What were you holding onto when you got shocked? Look in the phone book for motor rebuilders in your area. They can check and fix whatever is wrong. You do have a grounded power cord on this, right?
"You do have a grounded power cord on this, right?"And assuming you do, have you tested the outlet ground?CharlieI tell you, we are here to fart around, and don't let anybody tell you different. --K Vonnegut
If this has developed recently, there must be someplace touching bare wire. You have to chase down the entire cord and connections. A simple continuity test on each wire will point you in the right direction. I had a circular saw that gave me a little jingle every now and then. Turned out that one of the screws that held the handle together was making contact. I didn't notice it at first because I had to remove that screw to look at the switch. When my skin touched the screw head I was getting it.
Beat it to fit / Paint it to match
I've read all the posts so far on this. The drill press is older, but works just fine. I'd rather get this one fixed. I've spent a small fortune in new machines and fixtures for my shop recently. I'm starting up my woodworking business after having worked for someone else for a number of years. So I'd love to keep any further costs down related to my tools. Can you describe a continuity test to me. I used my multimeter and determined that all the metal parts on the drill press had a small voltage running through them. That pretty much exhausted my knowledge with troubleshooting electrical problems.It just happened that morning. I did trace all the wires I could find looking for a bare wire touching the housing, but everything looks great. Someone mentioned a problem with the motor, and I guess I may have to take the thing to someone to have it checked out. Maybe it would be cheaper to replace this thing, but everything else works just fine with it. Ralf
small voltage running through them.. How small? Voltage knockes ya off, Current kills and in wery small abounts 40 micro amps or so as I recall but I'm old and forgot..
Old tools are GREAT!. Get Ground Fault Outlets and rubber mats to stand on.. How about a helper to run them old tools?
Just funnin ya.......
Having the motor checked is fairly cheap. Take the whole thing in for them to look at- they can find out if it's the switch, motor, whatever. If they don't find it then, you know that the wiring where it's plugged in may have a problem. Again, if it's on a three way switched circuit, this may be the cause. If there's a problem with the neutral in the drill press or the panel, you can have issues, too. Whatever happens, this needs to be fixed.You referenced the base and motor to true ground, right? That's the main measurement you need to be concerned with. If you are touching the machine and are grounded(wearing somewhat conductive shoes on concrete is close enough), you become the load and are at risk of electrocution.
"I cut this piece four times and it's still too short."
Ground is GOOD! I worked with 480 motors all my life.. before I touched anything I checked the ground...
A continuity tester is just a light with two ends. Touch an end on each end of the wire, if you have a light, the wire is continuous, un-interrupted. I would follow others instructions about taking the unit to someone qualified. There are simple plug in ground checking devices for checking the outlet. If it's not the unit, which I doubt, call an electrician, you could have wiring problems. Continuity or any other such test won't tell you if you are wired wrong, reversing polarity.Beat it to fit / Paint it to match
Ralf,SO LONG AS YOU INTEND TO CONTINUE TO USE YOUR DRILL PRESS WITH THE SHORTED COMPONENTS,JUST ATTACH A GROUND WIRE TO AN HANDY PIPE AND THE MOTOR"S METAL HOUSING.
THIS MAY SAVE YOUR, OR YOUR KID"S LIFE.
Look in back of your washing machine or drier. See that bare wire attached to the metal drainpipe and the metal cabinet? That's a 'Wifesaver' On a previous post someone mentioned a phantom drillpress. Darn thing would turn on all by itself in the middle of the day .Just imagine yourself gripping the chuck while inserting a wicked sharp forstner bit??A lot of shop power tools have motors with overload protection
When the motor gets too hot, it automatically shuts down
THEN... When you least suspect it, it cools off and restarts on it's own. Nasty business that?BETTER to have all stationary power tools equipped with relay push button on -off switches.
If there's a power outage, the machines all shut down....But, they CAN,T restart all by themselves when the power returns. Steinmetz To use your continuity tester , Pull out the motors plug. With the switch in the OFF position, set your multimeter to Ohms.
When you touch the two probes together, the meter reads O resistance.
(That means you can be sure it's working and it's battery is not dead.)With the switch OFF, you should get no reading across the plug's prongs
With switch on, you should get a reading (Continuity) [no opens]To test for a short to ground,with switch on,
touch one lead to the motor's metal housing and the other lead to each of the two plug's prong's in turn. There should be NO reading if it's not grounded. (Good)If any of the prongs show continuity to the motor's housing, That's a short to ground (BAAD)[Shock hazzard] If after you plug in the motor and attach the new (Permanent) grounding wire, the motor runs, but no shock (GOOD) If motor won't run, it blew the circuit breaker but not you!
By "older Taiwanese" you mean cheap why not replace it with a new one?
Do you have ground fault outlets in the shop??? Not a cure ALL but sure helps!
About 8 t0 12 dollers.. Much cheaper en' a funeral..
Edited 1/30/2005 9:16 am ET by Will George
8 volts ac wouldn't even be noticed. To get your attention would take about 40V. You can feel less by running your fingers lightly across the offending item--feels like a hum in the fingertips. Anyway you aren't clear how you tested it. Did you attach one end of meter to a good ground (metal switchplate screw ought to do) and the other probe to the drill? Everyone with a shop should have one of those $5 outlet testers with the 3 lights that tell you if your outlets are wired correctly. Sometimes even licensed electricians make mistakes.
Another thought: Do you have a worklight attached to the drill press? I have one on my bandsaw that doesn't have a polarized plug and will make the whole saw "hot" if it's plugged in the wrong way.
Things like this don't happen if everything is wired to code:
-- The drill press frame should be grounded, through a 3-prong grounded plug. If this were the case, you wouldn't get a shock.
-- If the shop has a concrete floor, the branch circuit should have a GFCI, unless the drill press is on a dedicated outlet. The GFCI would prevent the shock as well.
If you don't see any frayed wire, the culprit is probably insulation on the motor wiring breaking down. If this is the case, time for a new or re-wound moter. And you need to bring your wiring up to code and make it safe.
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