1. Home
  2. ⚙ Model Engineering in the UK
  3. Electric motor problem

Electric motor problem

Firstly, lets establish that I am not an electrician..........

I have a pedestal drill, 3 phase, with a Memota (MEM) push button starter (NVR). Motor is the common "Hoover" style 1/3 or 1/2 horse, cant remember which.

The motor does not start on its own, you have to "spin" the chuck to get it to go under its own steam (Electric). Also, the motor seems to lack any real "guts", it will stop rotating fairly easily. The motor case seems to get reasonably hot to the touch.

This drill is only used for countersinking 16mm dia full depth in a pre drilled 10.5mm hole in mild steel. Its common to do a batch of 70+ countersinks in a session.

Would I be right in thinking 1 phase has gone down ?, if so, does it point to the motor or the starter ? Is there a test I can make to eliminate one or the other, or does my description of the problem already do this to the experienced person ?

A volt meter shows all 3 phases coming in to the starter from the supply source.

Help/advice most appreciated Bob

Reply to
Emimec
Loading thread data ...

Sounds like you've got an open circuit phase in the starter or motor.

In order or simplicity:-

Take the junction box cover off the motor and remove the wires coming from the starter. Arrange them so they won't touch anything (insulting tape, bit of wood, whatever...). Measure the voltage between said wires when starter is on.

That'll tell you if it's the starter or the motor. If the meter has got a resistance range, measure the coil winding resistances. Measure between phase and star point if visible. otherwise, measure phase to phase. Noticeable differences between the three readings will indicate an open circuit.

Taking the non-drive end off the motor and looking at the windings will indicate major magic smoke escape.

Regards Mark Rand RTFM

Reply to
Mark Rand

Many Thanks. Will do this Saturday morning. Bob

Reply to
Emimec

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.