Efco jolly wiring melt down....

[10/80]

Anyone have any ideas as to what has caused this?...It's the wiring between the three way switch and the motor.

 

[10/80]

 

[blades]

first thought is poor connections which would significantly raise the amperage draw, second would be motor load - bearings or some sort of significant drag causing high amperage draw. possible failing pole wiring in motor. in some 30+ years i have only managed to burn out one motor and that was an import from chicom territory. Crimp-on connectors and push on terminals are notorious for corrosion causing high amperage draw. Seen lots of burned off terminals from this.

 

[huskihl]

That would almost have to be a short inside the motor for there to be enough heat to burn insulation off that motor running on 220V. Or possibly a hot wire was rubbing against a ground and wore through the insulation. I believe mine is 1.5A or so at 120v. Yours should only draw about .8A.

 

[10/80]

I had noticed the motor felt hotter than I thought it should.
After I separated the wires the motor still runs.

 

[huskihl]

I had noticed the motor felt hotter than I thought it should.
After I separated the wires the motor still runs.

Maybe check the bearings and the brushes over real good? I honestly don’t know, I’m just spitballing

 

[10/80]

Maybe check the bearings and the brushes over real good? I honestly don’t know, I’m just spitballing

It's all a mystery to me too!....Guess I'll pull the motor and see.

 

[10/80]

Anyone know if a poorly grounded earth wire could cause this?......I noticed the earth wire was very loose, basically not contacting.

 

[10/80]

.....Not only was the earth loose, the intended contact surface had a layer of power coat covering it.

 

[Stump Shot]

.....Not only was the earth loose, the intended contact surface had a layer of power coat covering it.

Q. I see it is 220 volt, is it being supplied with the correct voltage?

 

[10/80]

Q. I see it is 220 volt, is it being supplied with the correct voltage?

The system here 240 volt.

 

[Stump Shot]

The system here 240 volt.

Well, then it's most likely like @huskihl said, something up with that motor.

 

[066 redeye]

Bad earth in not the problem.

 

[Lightning Performance]

Could be a hot loaded bearing starting to seize like Kevin said.

I've seen switches slowly going bad do horrible thing to high voltage wiring. High amp low volts makes even more smoke and mess but goes downhill much faster. Load test the main line to see what your loaded hot amps draw comes in at.

 

[10/80]

Just to rewind a bit.....I purchased the grinder second hand a few years ago and hadn't used it much, as I mentioned previously it seemed to run hotter than I thought it should?....It would appear that the previous owner had the unit apart and had over tensioned the four nuts securing the end plate on the motor, in turn this over loaded the bearings causing the over heating which caused the wiring to melt.

The four nuts in question are under the red fan cover...
The grinder now has new bearings, new wiring and is working as it should (and running cool).
Thanks for the replies and suggestions!