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  1. #1
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    Blown capacitor cause


    Yesterday I inspected a Vinco 24,000 BTU's splitunit. The unit was connected to a 13a Plug (BS1363). After a while running in cooling mode the 13a fuse was blown. The owner replaced the 13a plug with a 20a Double pole switch. The unit started normally but again after a while the capacitor was blown. The unit done it twice, blowing the compressor capacitor. Is the compressor overloading? Can anyone help, thanks



  2. #2
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    Re: Blown capacitor cause

    Could be a number of things...

    Voltage fluctuations, motor overload, motor overheating.

    I would suggest inspecting the compressor for motor failure along with the wiring circuit.
    Brian - Torquay, Devon, UK
    I have to stop saying "how stupid can you be?" to my co-workers.
    They're starting to take it as a challenge...

    BASIC MAINTENANCE. If it doesn't move and it should then use WD40. If it moves but it shouldn't then use Duct Tape.

  3. #3
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    Re: Blown capacitor cause

    Have you measured amerage draw, and looked at pressures and temperatures? Otherwise, you're shooting in the dark and guessing. Keep putting in larger and larger circuit protection devices and you'll solve the problem by burning out the gear. A bad burn out with burned up compressor insulation through the system and you're in for a complete fresh new build from the ground up.

  4. #4
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    Thumbs up Re: Blown capacitor cause

    hai..

    U also can troubleshoot step by step.

    1) I think better u disconnect cable which for compressor.then you start the unit.if the fuse still blown,that mean your condenser fan or your circuit wiring have a problem.

    If the fuse is ok,when you disconnect compressor wire,that mean your compressor have a problem.

    Good luck.

  5. #5
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    Re: Blown capacitor cause

    I am not familiar with the equipment model you have mentioned.

    Question...Did the capacitor blow up, or when you say "blown" do you mean that it failed?

    I am thinking that your original problem was a capacitor that was starting to fail.
    What can happen is that the capacitor will start to fail, perhaps partially, reducing overall capacitance, which reduces starting torque on the motor. Depending on where the motor stops the current draw can be huge on start-up, due to the loss of phase shift when a capacitor starts to breakdown. I have seen a capacitor short out and explode under these conditions

  6. #6
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    Re: Blown capacitor cause

    A capacitor mostly blows because it discharges too fast.
    That's also the reason why a resistor is fitted between the two poles.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  7. #7
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    Re: Blown capacitor cause

    I don't understand: at first the fuse blew, and later the capacitor blew. So apparently it is a different fault, is it?

  8. #8
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    Re: Blown capacitor cause

    The capacitor can blow if there is excessive current through it. There can be too much current if there is a short between winding turns in the compressor. It can also draw too much current if the compressor is pumping into a restriction, such as debris in a metering device or an expansion valve issue. I have watched a high pressure side peg out the gauge at 500 PSI due to a blocked expansion valve and then blow the circuit protection device. It will pay to make some measurements to figure out what's really going on.

    Also, is the replacement cap full spec for your application? A wrong capacitor even of the correct value and voltage rating can have excessive ESR (Equivalent Series Resistance) causing it to blow. A blown capacitior will take the circuit protection device out. That protects the compressor from damage.

  9. #9
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    Re: Blown capacitor cause

    Quote Originally Posted by NoNickName View Post
    I don't understand: at first the fuse blew, and later the capacitor blew. So apparently it is a different fault, is it?
    not realy, the problem is low voltage ore compressor filure (not necessary total failure) 13Amp and 20 Amp for a 24.000 BTU non inverter is not enough it should be somewhere at 24

    You should check the voltage if it's lower then 5% or more its a problem, and check if there are other big consumers that when started could make the voltage go under 5% if everithing is ok, u should check the amp drown from the compressor to see if there is a compressor failure

  10. #10
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    Re: Blown capacitor cause

    Quote Originally Posted by Larry2 View Post
    It can also draw too much current if the compressor is pumping into a restriction, such as debris in a metering device or an expansion valve issue. I have watched a high pressure side peg out the gauge at 500 PSI due to a blocked expansion valve and then blow the circuit protection device.
    .
    I am confused by this? If there is a blockage in a metering device, wont the system go into pumpdown, resulting in lower pressures, and lower current draw?

  11. #11
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    Re: Blown capacitor cause

    I had this on a cellar cooling unit - we replaced the compressor (ManEurope), it started fine but after a few minuites the run capacitor blew up. Changed it and its been fine since.

  12. #12
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    Re: Blown capacitor cause

    Quote Originally Posted by Takeshi View Post
    I had this on a cellar cooling unit - we replaced the compressor (ManEurope), it started fine but after a few minuites the run capacitor blew up. Changed it and its been fine since.
    Did you not replace the capacitor and start contactor/relay as a matter of course when changing the compressor ?
    Brian - Torquay, Devon, UK
    I have to stop saying "how stupid can you be?" to my co-workers.
    They're starting to take it as a challenge...

    BASIC MAINTENANCE. If it doesn't move and it should then use WD40. If it moves but it shouldn't then use Duct Tape.

  13. #13
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    Re: Blown capacitor cause

    Yeh - but ManEuope did not give us any capacitors or anything with the compressor , so we had to make do with what we had.

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