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  1. #1
    Join Date
    Feb 2011
    Location
    Illinois
    Posts
    52

    Liebert condenser with a P66 speed controller

    Went to a site today and found a Liebert condenser with 2 motors: 1 single phase motor which is normally controlled with a JCI P66 series speed controller and a 3 phase motor which is controlled by outside air temp. Over the weekend, the single phase motor died and someone hooked up the 3 phase motor to the P66 controller--and it is still running! I took current reading and it is slightly high <10%.

    According to the P66 literature, you cannot use on a 3 phase motor. How is this motor working?
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  2. #2
    Join Date
    Nov 2005
    Posts
    1,350
    When you figure it out let me know. I have never seen it done. Is the cap wired in? Does the speed change with an increase in pressure?
    I STARTED WITH NOTHING, AND I STILL HAVE MOST OF IT!

  3. #3
    Join Date
    Mar 2003
    Posts
    7,321
    guessing they wired it up as single phase and then helped start the fan manually. it will run for a while, but thne it will fail and they will need two new motors.

  4. #4
    Join Date
    Nov 2011
    Location
    British Columbia
    Posts
    48
    Gonna need two motors soon!

  5. #5
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,611
    Before you go changing motors, I had an APC system with Heatcraft condensers. 1 3ph fan controlled by OAT stat and 1 1ph fan controlled by P-66. 2 winters in a row I would get an after hrs call the unit is down on high head safety. By the time I got there reset the safety, everything worked fine. Both APC and Heatcraft got involved. Final speculation during cold operating conditions with the right wind speed and direction the p-66 would ramp to low causing the motor to over heat and cut out on thermal. There solution, install a P-70 inline with the start signal on the condenser.

    Give me a headmaster anytime!

  6. #6
    Join Date
    Oct 2011
    Location
    Cicero, IN.
    Posts
    48
    This has happened twice to me in the last 6 months on a Liebert. Running fine at the moment and not throwing parts at it.

  7. #7
    Join Date
    Feb 2011
    Location
    Illinois
    Posts
    52
    I went back and replaced the single phase motor. As far as the 3 phase motor, L1 was feeding through P66 serving as 1st ph, L2 was 2nd ph, L3 was fed from capacitor off of L2.

    I rewired appropriately, checked amp draw and all seems to be normal for now.

  8. #8
    Join Date
    Oct 2011
    Location
    Cicero, IN.
    Posts
    48
    pecmsg...Can you be more specific on the P-70???

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