Automatic Capacitor Discharging Recommendation

Discussion in 'General Electronics Chat' started by acvegas, Jan 7, 2011.

  1. acvegas

    Thread Starter New Member

    Jan 7, 2011
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    :confused:What resistor value and wattage value should I use to act as a “Bleeding Resistor” on a 26 MFD AC POWER CAPACITOR within a 120 Volt AC Line Circuit?
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I'd use a 120v incandescent lamp. It will discharge the cap very quickly while giving an indication of charge remaining by the light output.
     
  3. acvegas

    Thread Starter New Member

    Jan 7, 2011
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    AN ADDITIONAL NOTE: I would like to install a "permanent" resistor within the circuit to take care of this automatically. Would a 100K/5 Watt work? (I need actual values)? Thanks
     
    Last edited: Jan 7, 2011
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    A small 1/4 or 1/8 watt 1 Meg resistor would be enough.

    Would take less than a minute to bleed off the voltage. Probably quicker than you could get the chassis open.
     
  5. #12

    Expert

    Nov 30, 2010
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    Yes, a 100k 5 watt would work. In fact, a 100k 1/2 watt would work. Much cheaper than a 5 watt resistor, and 10 times as fast to discharge the capacitor as a 1 meg resistor.

    Watts Law: P=e^2/r
    P = 120^2/100000
    P=14400/100,000
    P=.144 watts

    half watt will work well. Bend "U" shapes in the legs when you attach it so it doesn't suffer mechanical stress from the heating and cooling that goes on in an air conditioner.
     
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