Coolmate 3 goes...... POP...!!! Any suggestions?

[piniongear]

I just got moved in and was tig welding up some pipe when I hear this loud single POP behind me.
The 'pop' was an electrical sound, and then I notice my Coolmate 3 is no longer running.
Does anyone have a suggestion on what may have blown? What approach is recommended to find the problem?
Thanks guys!
Perry

[Aeronca41]

Took a look at the manuals for a couple of random serial numbers; would need your ser no to verify, but the only thing electrical in there is a DPST power switch and a motor if you have the 120 volt version. The 230 V version only adds a fuse on each side of the line. Nothing else electrical to go wrong except wiring connections-you should be able to check those just by looking around inside. Next thing would be to check fuses if you have them, then temporarily bypass the switch and see if the motor runs. Please post your serial number. Good luck!

[piniongear]

Took a look at the manuals for a couple of random serial numbers; would need your ser no to verify, but the only thing electrical in there is a DPST power switch and a motor if you have the 120 volt version. The 230 V version only adds a fuse on each side of the line. Nothing else electrical to go wrong except wiring connections-you should be able to check those just by looking around inside. Next thing would be to check fuses if you have them, then temporarily bypass the switch and see if the motor runs. Please post your serial number. Good luck!

Thank you so much Aeronca41.
The serial number is LA050893.
I will open it up later this morning and see what I can find.
I will also bypass the switch to see if it runs.

The pop was a loud single pop while I was welding and then the Coolmate was dead.
Perry

PS: Yes, I have the 120 volt version.

[Midnightcaper]

how old is your coolmate?

[H80N]

Took a look at the manuals for a couple of random serial numbers; would need your ser no to verify, but the only thing electrical in there is a DPST power switch and a motor if you have the 120 volt version. The 230 V version only adds a fuse on each side of the line. Nothing else electrical to go wrong except wiring connections-you should be able to check those just by looking around inside. Next thing would be to check fuses if you have them, then temporarily bypass the switch and see if the motor runs. Please post your serial number. Good luck!

Excellent advice...........

would also check the wiring for frayed or cut insulation....

especially where wires contact or go through holes in the chassis/casework........

[Aeronca41]

https://www.millerwelds.com/files/owners-manuals/O628G_MIL.pdf

This link connects to your manual if you don't have one. There is a note on troubleshooting (p. 7) that indicates there must be a thermal cutout on (in?) the motor itself, which could also have failed. Probably a lot cheaper than replacing the motor if you're confident tearing it apart, should that be the problem. My guess is the switch or, as H80N said, a frayed wire somewhere that made the pop as it vaporized. Keep us posted!

[piniongear]

Thanks for the suggestions and help guys. I greatly appreciate it.
Now let me tell you what the problem was.......
I am in my new (new to me) house and shop. There are many circuits in the shop with an assortment of GFI's watching over the outlets. There must be 4 or 5 in the garage/shop alone.
The GFI would trip the instant I plugged in the cord to the Coolmate, even though the Coolmate switch was in the off position.

It was then that I noticed a green spiral running around the cord insulation.
This spiral was the inner green ground wire almost burning through the outer insulation.
Here is what caused that.........
I build steel rollers for an item I manufacture. These are 3 inch diameter DOM tubing which is mounted in a 4 jaw chuck in my lathe.
I face the end, then Tig weld an end plate to that.
Next I reverse the tube in the chuck, face off the end and weld another end cap on the end.

One time I welded an end cap in place without realizing that I had failed to attach the ground cable to the lathe.
The welding went fine, but then there was the "pop".
What happened was the current was seeking a ground and the only thing available was the small green wire in the power cord of the Coolmate.

Closer inspection found the insulation almost melted off the power cable with the 3 inner wires showing in places.
The GFI caught the problem and tripped.
Had I not had that GFI, I most likely would soon have myself an electrical house fire.
I learned a good lesson with this one!
Thanks again guys and I will keep telling myself to attach the ground cable from here on out.

[Aeronca41]

Wow, that's some chain of events! And, as you note, scary! You just don't think about potentially starting a house fire by failing to attach a welder's work cable. As somewhat of a student of the NEC and its updates for many years, it's been interesting to see how many people vehemently resist change, including grounding wires ("those crazy new 3-prong plugs"--many guys just cut off the grounding terminal on their power tool cords for years), 4-wire connections for ranges and dryers, then GFCIs, AFCIs, etc. all had their detractors. Sure is great you had the GFCI. Thanks for the very informative post.

[ryanjones2150]

Yikes.

I did something similar but not nearly as potentially catastrophic as that a while back....was doing some repairs to a tilt bed trailer. Had several repairs to make on this old painted and rusted frame, so I was stick welding it, good and hot. I had a good ground location on one of the forward members and life was good, for a while. As I moved down the frame to the tilt bed I didn't move my ground clamp with me. It would appear that the contact between the metal pivots of the tilt bed and the frame wasn't nearly as good as the trailer wiring. I struck an arc and heard WHIZZZZ ZZZIP POP!! Oops. Instantly fried the ground wire down the whole length of that trailer. I guess 16 ga wire doesn't make an acceptable welding ground lead.

[H80N]

Glad you found it..... Mystery Solved.....

[piniongear]

Yes, 16ga wire is a bit light to use as a ground. That is what I was using without knowing it.