The Emco Unimat motor failure for the second time, this one was slightly different in that I switched the motor on and the house earth leak detector tripped. The first time the motor failed it was because the brushes had just worn out.
A simple resistance measurement between the earth and neutral shows 50kOhm.
This is enough of a resistance to trip the earth leak detector on the house and it is a potential hazard and so a good job it was caught in this way.
The offending image that shows all of the carbon deposits and a bare wire where the brush connects to one of the main windings and hence Emco Unimat motor failure.
I cleaned the motor out with a vacuum cleaner and then wiped it as best I could with a cloth and alcohol.
Some shrink wrap over the offending wire is enough to stop the earth leak.
Note: you really do need to know your way around electrics and to get any work checked by a professional. Please take care and get the right person to check it out.
Motor failure sorted, I reassembled the motor, check the neutral to earth and live to earth and found them both to be open circuit.
The motor now runs again like a dream. This motor has now been operational for more than 40 years.
As I’ve said several times, this isn’t the best motor as it is underpowered and gets very hot in use. Hence it can only be used for around 10 minutes before leaving it to cool down for 30 minutes. I’ve constructed a page that is all about alternative motors for the Emco Unimat 3.