plentywahalla
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| posted on 2/12/13 at 10:56 AM |
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An Electric Motor question
This is a question for those of you who know these things, its all a black art to me!
I have a 230 volt ac 600w capacitor run motor on a pump.
It stopped running and just humms. That usually means that the capacitor has blown so I replaced the 15 microfarad capacitor and tried again. Same
result it just hums and when manually spun in correct rotation, nothing!
The odd thing is than when I take the capacitor out of circuit so each set of windings is powered directly, and give it a spin it runs perfectly. With
the capacitor in circuit, nothing. I have tried putting the capacitor in series with the other set of windings and giving it a spin (backwards) I
still get nothing.
My understanding is that a capacitor run motor works by creating effectively a 2 phase supply by the capacitor creating a delay in the second set of
windings. If so the above shouldn't happen.
Any answers?
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
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Ashley Jenkins
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| posted on 2/12/13 at 11:12 AM |
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I would test continuity/resistance of starter winding. It sounds like it might be open circuit hence why when spun manually the motor will run
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big-vee-twin
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| posted on 2/12/13 at 12:06 PM |
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Check the centrifugal switch, probably burnt out.
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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David Jenkins
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| posted on 2/12/13 at 02:14 PM |
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quote:
Originally posted by big-vee-twin
Check the centrifugal switch, probably burnt out.
That was my first thought... or maybe dirty contacts.
There used to be a useful electric motor rewinding company on the Hythe in Colchester. They gave me a lot of help a long time ago when I needed new
bearings in a motor - might be worth a quick look in yellow pages to see if they're still around.
(found them - they've moved - Colchester Rewind & Repair, Moss Road, CO3 0LE)
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plentywahalla
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| posted on 2/12/13 at 02:35 PM |
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quote:
Originally posted by big-vee-twin
Check the centrifugal switch, probably burnt out.
Its a capacitor run motor, there isn't a switch.
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
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MikeRJ
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| posted on 2/12/13 at 03:56 PM |
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Sounds to me like the main winding could be open circuit. By removing the cap and connecting mains directly to the capacitor winding, you would get
it to run (with low torque) but it wouldn't be self starting.
Have you checked both windings for continuity with a multimeter?
[Edited on 2/12/13 by MikeRJ]
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big-vee-twin
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| posted on 2/12/13 at 06:47 PM |
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Capacitor motors have a centrifugal switch to switch the cap and start winding out of circuit once it's up to speed.
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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plentywahalla
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| posted on 2/12/13 at 07:07 PM |
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quote:
Originally posted by MikeRJ
Sounds to me like the main winding could be open circuit. By removing the cap and connecting mains directly to the capacitor winding, you would get
it to run (with low torque) but it wouldn't be self starting.
Have you checked both windings for continuity with a multimeter?
[Edited on 2/12/13 by MikeRJ]
You're right .... I opened it up and there was a break in the wire to the main windings. I soldered it back together and the motor starts and
runs fine now.
What fooled me was that I assumed it was running at full torque when spun up manually. It wasn't ... after I had fixed it it leapt off the bench
and onto the floor!
Thanks Mike
Richard
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
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