Me: "Try over revving it when it starts and see if that causes it to energise, or bigger cap for a test....."
You: "Finally some sucess i revved the motor up at start up and it will energize"
Tells me that the cap is down or the revs are too low.
"Do you think that it could be just a matter of raising to idle speed"........There is no idle, they must run all the time at 3600rpm for your frequency... other wise the voltage is wrong for a start, the frequency is wrong for a second, and it wont energise for a third.
If you want to run slower for some reason, (quieter and dont need the freq correct nor voltage correct... ie driving hand tools with universal motors etc), then you will need a slightly bigger cap, and it will start lower and run lower, but your frequency will be wrong but the voltage may still right. (due to the extra excitation, the voltage will kick up, but the frequency is tied to rpm only).
good to see it working again .
..............oztules
Edit: Dinges there is a lot of truth in that, but if so, then it would not run normally once flashed. It needs the diodes all the time, not just at start up........ having said that, they will run on one diode..... but very poorly regulated... ie sags very much under load.
