Brook Crompton Parkinson single phase PD90S (from the 70s) 240v 11A 2850rpm 50hz
I'm using it for polishing metal with a tapered spindle adapter and buffing wheels.
I've got 2 questions.
1. (This photo was taken with all the wiring in its original position.)
I've managed to reverse the motor rotation by swapping the two black wires that are behind the copper connector, but after a few quick trials it is constantly blowing fuses.
Can you confirm that I have changed the correct wires to reverse the rotation?
2. The capacitor starts the motor with a massive jolt which forces the buffing wheel so far onto the tapered spindle that I need large pliers to loosen the buffing wheel.
If I fitted a smaller capacitor would it start more gently or is it possible to remove the capacitor and start the motor by hand by rotating the buffing wheel?
The white arrows point to the three wires that go inside to the motor.
![[ElectriciansForums.net] Single phase motor reverse rotation](/proxy.php?image=https%3A%2F%2Fi.ibb.co%2FtHk0kXW%2FP1010335.jpg&hash=e400f031d6cc96ccc93cd04070f88089 "[ElectriciansForums.net] Single phase motor reverse rotation")
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UPDATE.
I just sorted the problem of blowing fuses.
I fitted new bearings to the motor a couple of days ago and noticed straight away that the motor was more stiff to turn and wouldn't turn freely if twisted by hand.
I thought that was just the bearings being a tight fit, but I slackened the 3 long bolts that hold the whole casing together by just a touch and it loosened the shaft a lot and it now can spin freely by giving it a quick twist.
It now spins for a long time after the motor is switched off which it didn't do before.
So I've tightened the 3 bolts just enough to keep the motor spinning freely.
But I still have the problem of the capacitor starting the motor with too much force.
I have a metal tapered spindle slid onto the splined end of the shaft which is a fairly tight fit.
That is then held in position by a 6mm screw to stop it rotating on the shaft.
The capacitor starts the motor so violently that the 6mm screw can't hold the tapered spindle on.
I have managed a work around just now of spinning the buffing wheel by hand as fast as I can, then switching the motor on while the wheel is already spinning.
[automerge]1582900603[/automerge]
And the motor is now spinning in the direction I want and working fine so my original question about what wires to swap seems to be answered too.
I'm using it for polishing metal with a tapered spindle adapter and buffing wheels.
I've got 2 questions.
1. (This photo was taken with all the wiring in its original position.)
I've managed to reverse the motor rotation by swapping the two black wires that are behind the copper connector, but after a few quick trials it is constantly blowing fuses.
Can you confirm that I have changed the correct wires to reverse the rotation?
2. The capacitor starts the motor with a massive jolt which forces the buffing wheel so far onto the tapered spindle that I need large pliers to loosen the buffing wheel.
If I fitted a smaller capacitor would it start more gently or is it possible to remove the capacitor and start the motor by hand by rotating the buffing wheel?
The white arrows point to the three wires that go inside to the motor.
[automerge]1582900380[/automerge]
UPDATE.
I just sorted the problem of blowing fuses.
I fitted new bearings to the motor a couple of days ago and noticed straight away that the motor was more stiff to turn and wouldn't turn freely if twisted by hand.
I thought that was just the bearings being a tight fit, but I slackened the 3 long bolts that hold the whole casing together by just a touch and it loosened the shaft a lot and it now can spin freely by giving it a quick twist.
It now spins for a long time after the motor is switched off which it didn't do before.
So I've tightened the 3 bolts just enough to keep the motor spinning freely.
But I still have the problem of the capacitor starting the motor with too much force.
I have a metal tapered spindle slid onto the splined end of the shaft which is a fairly tight fit.
That is then held in position by a 6mm screw to stop it rotating on the shaft.
The capacitor starts the motor so violently that the 6mm screw can't hold the tapered spindle on.
I have managed a work around just now of spinning the buffing wheel by hand as fast as I can, then switching the motor on while the wheel is already spinning.
[automerge]1582900603[/automerge]
And the motor is now spinning in the direction I want and working fine so my original question about what wires to swap seems to be answered too.
Last edited:
