- Thread starter Bsmith
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@Bsmith , I've taken another look at your photos and it appears you have wired it as suggested earlier.
If the motor repeatedly cycles on the start winding I would check your connections on the run winding for continuity and check/replace the run capacitor. Any smallish value will do but make sure the voltage rating is sufficient. You could even simplify the wiring during testing by omitting the start winding and spin the motor with a length of cord, but be extremely careful how you do this! Do not power the motor while the cord is still attached to the output shaft.
If the motor repeatedly cycles on the start winding I would check your connections on the run winding for continuity and check/replace the run capacitor. Any smallish value will do but make sure the voltage rating is sufficient. You could even simplify the wiring during testing by omitting the start winding and spin the motor with a length of cord, but be extremely careful how you do this! Do not power the motor while the cord is still attached to the output shaft.
I was testing the run windings with the run cap connected when I was getting no ohms reading, forgot that indeed they were showing 2.6ohms before. I will disconnect run windings from everything and try again.
I did actually try another capacitor on the run windings which was 250v 10uF, it made no difference.
I did actually try another capacitor on the run windings which was 250v 10uF, it made no difference.
Thankfully I was aware of this and happy to have earthed the start cap before disconnecting, it produced a blue spark like a motor spark plug and a loud crack like a stick breaking.
My mistake, apologies, last time when getting no reading I was testing the run windings with the capacitor connected.
Hopefuldave
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Nope, the start winding needs to be connected through the run cap (20uF), AND through the centrifugal switch and start cap (150uF) - otherwise it'd only have a single cap in it...
yep the windings should be almost a short, if you can spin the motor shaft quickly the centrifugal switch will open - go from short to open circuit (wrap a piece of cord around the shaft and give a mighty yank on it?)
If you need it to reverse, swap both leads to ONE of the windings - the 3-pole drum switch is a good'un for this
Both caps ------> start windings?
Run windings L and N.
I will give it a try when I get back to the shed, but got a few other things on over the weekend
Hopefuldave
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yep, the run cap puts a phase shift on the start winding once it's up to speed to maintain the roatating field, it needs more current at startup so the start cap's put in parallel as bigger capacitance = lower AC impedance. Understand that start caps aren't "continuously rated" and if left in circuit do a very good impression of a Hercules firing off chaff... run caps are differently constructed, which is why they're so much bigger for the same value / less capacitance for the same size. Don't get them swapped....
[edit] oh, the centrifugal switch can go either side of the start cap, i.e. between live and cap, or between cap and start winding, as long as it's in series it doesn't matter [edit]
[edit] oh, the centrifugal switch can go either side of the start cap, i.e. between live and cap, or between cap and start winding, as long as it's in series it doesn't matter [edit]
That's interesting, and I'm happy to be corrected. If that turns out to be correct, the "start" winding will really be an auxiliary winding which also serves as a start winding. I've had a look online and that setup appears to be common.
Ok if I was wanting to reverse the rotation it would be a case of swap the wires over on the start windings as I don't see it making any difference swapping the Live and neutral on the run windings? Maybe it does though?
Think I would put the centri switch inline before the start cap as less current would be going through the little contacts then.
But please tell me if I am wrong as interesting stuff.
Think I would put the centri switch inline before the start cap as less current would be going through the little contacts then.
But please tell me if I am wrong as interesting stuff.
Current will be the same, before and after the capacitor.
Hopefuldave
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The centrifugal switch, start capacitor and start (or aux, see good point from 6ply) winding are all in series, so the same current HAS to flow through the start cap and centrifugal switch - the switch will (unless the motor's crap!) have nice big, fat, contacts held firmly together by a spring, normall no need to worry about it.
Reversing either of the windings will do - not both - because the phase shift from the capacitors means the current (and so the magnetic field) "lags" behind the main winding, imagine it stepping round the windings' poles - if the order changes by reversing one winding's connections, the steps go in the opposite direction.
Reversing either of the windings will do - not both - because the phase shift from the capacitors means the current (and so the magnetic field) "lags" behind the main winding, imagine it stepping round the windings' poles - if the order changes by reversing one winding's connections, the steps go in the opposite direction.
Pete.
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Swap either it doesn't matter. The start winding supplies a bias working with the run winding to cause the motor to turn a particular direction. Reversing either will reverse the starting direction.
Tested the windings today again and the run windings show as 2.6 on the lowest setting on the multimeter. The start windings show as almost a short, is this high or low resistance?
Anyway, the motor starts and runs fine wired as the pic below, even revolves in the direction I want it to.
Thank you fellas for all the help, I really appreciate it.
Anyway, the motor starts and runs fine wired as the pic below, even revolves in the direction I want it to.
Thank you fellas for all the help, I really appreciate it.
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