Capacitor check on furnace. - Page 2
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  1. #14
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,778
    Quote Originally Posted by Hwolfe View Post
    I would check your amp draw on your motor after replacing capacitor to insure condition of the motor.
    Yes checking amps is a good thing, but I never check just amperage until after I have check voltage.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  2. #15
    Join Date
    Sep 2012
    Location
    NW Louisiana
    Posts
    159
    Quote Originally Posted by Mr Bill View Post
    Yes checking amps is a good thing, but I never check just amperage until after I have check voltage.
    Low voltage will make the amps climb... Then we find loose connections, and burnt wires, and well you know the rest.

    CT

  3. #16
    Join Date
    Jul 2007
    Posts
    65
    Changed cap ,motor hummed, gave blower spin to get going, noisy as hell, berrings are shot, going to replace motor. Thanks all for help.

  4. #17
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,778
    Quote Originally Posted by iceage View Post
    Changed cap ,motor hummed, gave blower spin to get going, noisy as hell, bearings are shot, going to replace motor. Thanks all for help.
    Motor runs hot on low mfd. cap. washes oil out of bearings, possible scenario.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  5. #18
    Join Date
    Jun 2010
    Location
    Miami
    Posts
    257
    I would be careful saying a run capacitor's main job is to correct power factor.

    I'd rather say the capacitor shifts the phase of one of the windings so that the voltage across the winding is at 90° from the other winding. The effectivly makes it a two-phase motor (when loaded).


    Now if the proper capacitor is used......then the currents through each of the windings, when fully loaded, should be equal....and under those conditions power factor will be close to 100%.

  6. #19
    Join Date
    Sep 2012
    Location
    NW Louisiana
    Posts
    159
    Quote Originally Posted by Russ57 View Post
    I would be careful saying a run capacitor's main job is to correct power factor.

    I'd rather say the capacitor shifts the phase of one of the windings so that the voltage across the winding is at 90° from the other winding. The effectivly makes it a two-phase motor (when loaded).


    Now if the proper capacitor is used......then the currents through each of the windings, when fully loaded, should be equal....and under those conditions power factor will be close to 100%.
    I agree 100%. In a nutshell, this is what I was trying to explain, but it did not come out as cleanly as you described. I was thinking about the phase angles and the reactance the capacitor adds to shift the angle.

    Thanks for the input. My wordiness probably confused some readers.

    CT

  7. #20
    Join Date
    Jul 2011
    Posts
    20
    Quote Originally Posted by nsula_country View Post
    1.2 mfd vs 5 mfd? This is off 76% of a 5 mfd cap. Most caps are (+/-) 5%-10% tolerance. Change is good!

    CT
    X2

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