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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. Its so close... A new capacitor is about \$ just change it
Last edited by beenthere; 09-10-2011 at 06:33 AM. Reason: price

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

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## cap

Originally Posted by Redwood650
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%

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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. 7.5X.06=.45
7.5-.45=7.05

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7.5x.94=7.05

8. Originally Posted by deon
7.5x.94=7.05
what's the .94? never seen this

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Originally Posted by Southern Mech
what's the .94? never seen this
sorry 7.5 x .06 = 0.45

10. Originally Posted by Southern Mech
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.

11. Originally Posted by Southern Mech
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. Originally Posted by hvacrmedic
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.

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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

Originally Posted by hvacrmedic
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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