# Short Circuit in Drill?



## gregzoll (Dec 25, 2006)

It sounds like you have a motor going bad. Especially that one point it will trip the breaker. But if you rotate the chuck, to turn the stator out of where the shorted winding loop is. Then it runs.

Time to toss it and get a new Hammer drill. Milwaukee drills are poorly made these days. Not enough Resin is used to coat the wiring for the motors these days.


----------



## de-nagorg (Feb 23, 2014)

That commutator appears to have wear lines, are the brushes decent?


ED


----------



## justplumducky (Aug 7, 2009)

de-nagorg said:


> That commutator appears to have wear lines, are the brushes decent?
> 
> ED


 Brushes are good. Solid contact with commutator, if that's what you meant. If you're speaking of the darker area on the commutator (wear lines), seems to me that's just discoloration, dunno .. from the brushes. 



gregzoll said:


> It sounds like you have a motor going bad. Especially that one point it will trip the breaker. But if you rotate the chuck, to turn the stator out of where the shorted winding loop is. Then it runs.
> 
> Time to toss it and get a new Hammer drill. Milwaukee drills are poorly made these days. Not enough Resin is used to coat the wiring for the motors these days.


 Even after moving the rotor, it will still trip the panel breaker. This one's about 30 years old - bought new and not that much use. 

*There shouldn't be continuity between the Field coil and the commutator, correct? * I suppose I should go on and dis-assemble the rest of it. Am puzzled as to what happened that it's tripping a breaker now, because it was running fine up to the point when the switch broke. Would sitting outside in an unheated shed for a long time (hot and cold seasons for several years) erode the insulation on the field windings, but even if it did, would that cause an immediate tripping of a breaker? Asking because...

... I once had an A/C condenser fan motor slow down very fast, then stop, after running for a few minutes, The fan blades wouldn't budge if you tried to move them with a screwdriver. Someone told me that was because of worn-off insulation on windings, which caused an opposing magnetic field to slow it down to a stop, then hold it in place. Power off, then it moves freely again, and will restart no problem, but then repeat the same thing.

Just checked for grounding from field coil first (none), then commutator to ground (none). No continuity from any of the terminals on the new switch - to ground.


----------



## de-nagorg (Feb 23, 2014)

There will be continuity from the commutator, through some of the field coil, through the brushes. 

Do your homework in electric motors, then try again.


ED


----------



## justplumducky (Aug 7, 2009)

Closer pic of the brushes and commutator.


----------



## gregzoll (Dec 25, 2006)

Oh, that is toast. 30 years of use. You got some good years out of it. Unless you have a local motor shop that can rebuild the motor on it. Cheaper these days to just replace with a newer unit.


----------



## justplumducky (Aug 7, 2009)

gregzoll said:


> Oh, that is toast. 30 years of use. You got some good years out of it. Unless you have a local motor shop that can rebuild the motor on it. Cheaper these days to just replace with a newer unit.


I did say it was about thirty years old, but also said "not that much use." That's why I'm puzzled, because it was running fine up to the point of the switch breaking. I'll take more of it apart tonight or tomorrow morning, see what I can see...


----------



## gregzoll (Dec 25, 2006)

I would not take it further apart to investigate. Unless you want to part it out for scrap, etc. I would just go get another one. If it sat for a long time. Any moisture that gets on the rotor or stater, will actually cause the resin to be eaten away by the rust. In turn you get open spots, that can cause shorts when the tool is used.

Like I stated before. If you have a local motor rewinding shop. Take it in there and see if it is even worth the cost to have them rebuild the motor. Otherwise, just go get a new unit.


----------



## junkcollector (Nov 25, 2007)

I wouldn't throw it away yet...

I would double check the connections on the switch. I'm wondering if you may have it wired into a direct short? Take a meter set on ohms and connect each lead to the two lead prongs of the cord; when you squeeze the trigger you should have continuity, usually somewhere around 5-20 ohms. If you have zero or close to it, you have a short. Now disconnect the two wires that go to the motor. Squeeze the trigger again. There should be no continuity- If you have it, you need to take your meter and figure out what terminals make and which break when you squeeze the trigger. Can you take a photo of the switch so I can see the connections?


----------



## justplumducky (Aug 7, 2009)

junkcollector said:


> I wouldn't throw it away yet...
> 
> I would double check the connections on the switch. I'm wondering if you may have it wired into a direct short? Take a meter set on ohms and connect each lead to the two lead prongs of the cord; when you squeeze the trigger you should have continuity, usually somewhere around 5-20 ohms. If you have zero or close to it, you have a short. Now disconnect the two wires that go to the motor. Squeeze the trigger again. There should be no continuity- If you have it, you need to take your meter and figure out what terminals make and which break when you squeeze the trigger. Can you take a photo of the switch so I can see the connections?




Ohms between HOT and Neutral prongs (black & white) on cord-set plug: .4 Ohms
Ohms between HOT and Neutral (black & white) on cord-set plug with #5 & #6 (leads going to motor) disconnected (see link for Wiring Instructions .PDF file online): Also .4 Ohms

*Wiring Instructions .PDF file:*
http://genuinemilwaukee.yolasite.com/resources/58-01-0182.pdf

SEE NEXT POST, PROBABLY ALMOST OUT OF TIME TO EDIT THIS ONE


----------



## justplumducky (Aug 7, 2009)

justplumducky said:


> Ohms between HOT and Neutral prongs (black & white) on cord-set plug: .4 Ohms
> Ohms between HOT and Neutral (black & white) on cord-set plug with #5 & #6 (leads going to motor) disconnected (see link for Wiring Instructions .PDF file online): Also .4 Ohms
> 
> *Wiring Instructions .PDF file:*
> http://genuinemilwaukee.yolasite.com/resources/58-01-0182.pdf


I had this new switch wired per the WIRING INSTRUCTIONS (link immediately above) as you can see in my attached pic (previous post). Apparently, the switch is defective or it's the wrong switch.

While ohms-checking the terminals like you said, I started to pay more attention to the path of all the wires. Understand now what you were getting at, relative to determining what terminals make & break when trigger is pulled, so I can route the power accordingly (if this switch is not defective, but just the wrong one). I'll report back tomorrow. 

I disconnected all the wires from the switch and jumped 120v power directly to the two leads going to the motor. IT RUNS!

j-collector, THINK I'M STARTING TO LIKE YOU!:laughing: :thumbsup:


----------



## justplumducky (Aug 7, 2009)

justplumducky said:


> I had this new switch wired per the WIRING INSTRUCTIONS (link immediately above) as you can see in my attached pic (previous post). Apparently, the switch is defective or it's the wrong switch.
> 
> While ohms-checking the terminals like you said, I started to pay more attention to the path of all the wires. Understand now what you were getting at, relative to determining what terminals make & break when trigger is pulled, so I can route the power accordingly (if this switch is not defective, but just the wrong one). I'll report back tomorrow.
> 
> ...


I don't know which was wrong... the switch (had the model and serial no. correct when ordering) or the WIRING INSTRUCTIONS. Maybe they knew it wouldn't work per the wiring instructions and expected me to figure it out and wire it up so it would work, Nah, too risky.. messing with my circuit breaker like that . I'll be asking them about it. To their credit however (ereplacementparts.com), I have ordered a few parts from them now and will continue to do so. Prices are good in my experience, delivery good to reasonable, easy to find the parts on their site. Have some videos online also. 

Anyway, my hammer drill is hammering away once again! Thx to all who responded! 

Sorry about my comment "THINK I'M STARTING TO LIKE YOU!" j-collector, cause actually.... 
Now I THINK I LOVE YOU MAN!! :yes::thumbup:


----------



## junkcollector (Nov 25, 2007)

Well, I wouldn't get too carried away.:laughing:

I'm glad you figured it out. It would have been a dirty shame to throw away a perfectly good tool like that. They just don't make stuff like that anymore.


----------



## del schisler (Aug 22, 2010)

justplumducky said:


> I did say it was about thirty years old, but also said "not that much use." That's why I'm puzzled, because it was running fine up to the point of the switch breaking. I'll take more of it apart tonight or tomorrow morning, see what I can see...


problum fixed


----------

