Failed compressor/motor


I have a small airless compressor which now has ceased to run. The first symptom was that it tried to start but behaved as though it was jammed - i.e. hummed but did not turn. It now won't do anything. It appears to be driven but a capacitor-start induction motor. If I'm right, is the fault likely to be the starter? There is no smell of burnt-out wiring, so I don't think it is the motor itself. The motor and air pump turn perfectly freely by hand.
This state of affairs arose without warning when I went to use the compressor today. It was not a case of using it for an extended period and then it expiring.
Does anyone have any ideas, please?
Rob Graham
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The capacitor may have died. What value is written on it?
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Andrew Gabriel

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20 microfarad
Rob
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So at 50Hz, it should have an impedance of approx 160 ohms. If you connect it in series with 100W or 150W light bulb, it should cause the light to be reduced to around half brightness -- this is the easiest way to test it. If the light is either full brightness or doesn't light, then the capacitor is dead (shorted or open circuit respectively).
--
Andrew Gabriel

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writes:

If that's a viable test, Andrew, then it looks as though the capacitor is OK because the lamp lights at full brightness.
Rob
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Rob graham wrote:

"If the light is ... full brightness ... then the capacitor is dead"
--
Sue

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writes:

Oops! Not reading correctly. Yes, the capacitor must be dead.
Rob
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http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU 02884&NA1 http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU 00006&NA1 http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU 00013&NA1 http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU 00022&NA1 http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU 00149&NA1
--
--
Andrew Gabriel
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writes:

This has all been very helpful of you Andrew. Thank you very much. I'll let you know if it works when I've finished!
Rob
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