Myford Capacitor problem?

[Les Jones 1Participant @lesjones1]

Hi Chris,
It looks like the 1 display is your meters way of indicating over range. ((Very high resistance value.) I tried to check the start winding resistance on the motor on my pillar drill. Only two wires come into the connection box from the inside of the motor so I could not check the resistance without taking the motor apart. All your readings are reasonably sensible values so I do not know what the fault is. I was expecting the "P" and "Z2" to be higher indicating a fault with the centrifugal switch. It is just possible that the centrifugal switch has slightly high contact resistance but this is very unlikely. If your other motor is identical you could compare the readings. It is looking like there is a fault with one of the windings.

Les.

[Chris TriceParticipant @christrice43267]

I'm coming to that conclusion. I feel another strip down coming on and a more detailed check for swarf or burning/pitting somewhere in the motor. The frustrating thing is it's worked perfectly for years with no failures or hiccups then suddenly, doesn't work with no warning or indicators of what the problem is.

[Neil LickfoldParticipant @neillickfold44316]

My motor had problems back in 2005. I thought it was a cap problem, so took the motor off and to a place to check it out. The man un soldered the cap,tested it and said it was all fine. I took it apart, he looked at the brushes in the switch, although not perfect he said that it still should have been working. I put it all together, he soldered back on the cap, connected some wire and worked fine. He said that sometimes over time, the soldered connection of the wires to the cap need re soldering. I took it all apart as I thought that there was a problem with the centrifugal switch. I was wrong.

It worked faultlessly until 2012, when everything stopped again. This time it was the forward and reverse switch that went. So I retired the motor and put on a 3phase motor with a VFD drive. The motor still works fine, and is sitting on the shelf as a spare for something one day.

[Clive HartlandParticipant @clivehartland94829]

The motor on my sawbench started to get hot and sometimes stopped mid run, I could not get a replacement as it was a double ended shaft type with pulleys at both ends. I took it to a local rewind place, just 2 chaps and quite a lot of test gear. They set it up and ran it for a moment and it showed that the start windings were not switching out. They rewound it and put in a new switch and it works fine, a bit expensive but as there was no hope of a replacement motor justified. Put it in the hands of a qualified motor rewind service, they will fix it or supply a new one.Wondering whether its a capacitor or a winding, is a fault waiting to come back and bite you later.

Clive

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