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Thread: mfd capacitor

  1. #1
    Join Date
    May 2011
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    mfd capacitor

    hi i would like to know if i have a good run capacitor but dont understand how to do the math on the mfd it is a 7.5 cap and it reads 7.02 is this a good cap and tolerance is 6% how do you calculate the math to tell its good or bad
    Thanks

  2. #2
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    Jun 2010
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    Its so close... A new capacitor is about $ just change it
    Last edited by beenthere; 09-10-2011 at 06:33 AM. Reason: price
    HOW MUCH DID YOU SAY???

  3. #3
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    Jun 2011
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    Most people I talk to say they go as far as 10%. I personally go off whatever the cap says. Id recommend replacing it.

  4. #4
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    cap

    Quote Originally Posted by Redwood650 View Post
    Most people I talk to say they go as far as 10%. I personally go off whatever the cap says. Id recommend replacing it.
    hey thanks but i still want to know how you come to the -6 +6 do you take 7.5 x .06 = 0.45 what is 6%

  5. #5
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    May 2011
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    cap

    hey thanks but i still want to know how you come to the -6 +6 do you take 7.5 x .06 = 0.45 what is 6%
    i want someone to do the math for me here so i can see the steps

  6. #6
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    7.5X.06=.45
    7.5-.45=7.05
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  7. #7
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    7.5x.94=7.05

  8. #8
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    Quote Originally Posted by deon View Post
    7.5x.94=7.05
    what's the .94? never seen this
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  9. #9
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    Quote Originally Posted by Southern Mech View Post
    what's the .94? never seen this
    sorry 7.5 x .06 = 0.45

  10. #10
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    Quote Originally Posted by Southern Mech View Post
    what's the .94? never seen this
    .94 = 94% or 6% less than 100%.

    So if the capacitor is less than 94%, it is outside the 6% tolerance.
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  11. #11
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    Quote Originally Posted by Southern Mech View Post
    what's the .94? never seen this
    It's 1 - 0.06.

    A little algebra:

    7.5 x 0.06 = 0.45
    7.5 - 0.45 = 7.05

    Substitute the left side of eq.1 for the 0.45 in eq.2. You get

    7.5 - 7.5 x 0.06 = 7.05

    factor out the 7.5 to get

    7.5 (1- 0.06) = 7.05

    or

    7.5 x 0.94 = 7.05

  12. #12
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    Quote Originally Posted by hvacrmedic View Post
    It's 1 - 0.06.

    A little algebra:

    7.5 x 0.06 = 0.45
    7.5 - 0.45 = 7.05

    Substitute the left side of eq.1 for the 0.45 in eq.2. You get

    7.5 - 7.5 x 0.06 = 7.05

    factor out the 7.5 to get

    7.5 (1- 0.06) = 7.05

    or

    7.5 x 0.94 = 7.05
    Or IOW 94% of 7.5.

  13. #13
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    May 2011
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    hvacmedic

    Excellant thats what i wanted to know thanks man and all you other people i appreciate it i never knew this


    Quote Originally Posted by hvacrmedic View Post
    It's 1 - 0.06.

    A little algebra:

    7.5 x 0.06 = 0.45
    7.5 - 0.45 = 7.05

    Substitute the left side of eq.1 for the 0.45 in eq.2. You get

    7.5 - 7.5 x 0.06 = 7.05

    factor out the 7.5 to get

    7.5 (1- 0.06) = 7.05

    or

    7.5 x 0.94 = 7.05

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