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  1. #1
    Join Date
    Jun 2019
    Location
    So Cal
    Posts
    375
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    Partial power failure

    Yesterday we had one phase go partially down, only 90-140 volts were coming in and would fluctuate.
    It all started when i noticed on our controls page that the system had gone "offline" there was no communication with the controllers.

    I head up to the roof top to find the whole system down, its "ON" but not running.

    Our multi stack direct control panel showed both our compressors on bearing motor fault, our vfd's displayed "external interlock".

    To make it short, our whole system was down, all 3 cooling towers, our joy fans and our compressors.

    To say the least i was lost, i had never experienced this, I tried what i thought was best , like setting our vfds to manual trying to get our joy fans and exhaust fan to come on. Only for 10 sec would they come on and then turn off immediately.

    Well we had our service company come out and their tech got to working, he concluded that one of the phases was "dropping" and we had insufficient voltage to get our motors running, ( apparently turbo core compressors are very delicate and will not run if all 3 phases are not proper.

    To add to the problems, the same phase that was causing our problems was also the one used to provide for our 120 volt circuits, which had our lighting flickering the whole time.

    A 3rd party electrician that does work at our building came out and diagnosed it as a bad, "gear box/ bar".

    A generator has been brought to provide power, while parts arrive and are replaced.

    While it was a head scratcher, it was also such a good experience for me to see all this go down and also inspiring seeing how the "big dogs" get down and dirty.

    The A/c tech was such a badass, he diagnosed the problem within 30 minutes!!!

    I hope to be like him one day.

  2. #2
    Join Date
    Jul 2018
    Location
    Wisconsin
    Posts
    1,095
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    Get some phase monitors. Will save your compressors and motors that are not on drives. The VFDs will be smart enough to fault out.

    Sent from my SM-G960U using Tapatalk

  3. #3
    Join Date
    Jun 2019
    Location
    So Cal
    Posts
    375
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    Thread Starter
    Quote Originally Posted by Spitz View Post
    Get some phase monitors. Will save your compressors and motors that are not on drives. The VFDs will be smart enough to fault out.

    Sent from my SM-G960U using Tapatalk
    The compressors will "supposedly" be replaced this winter break, lets see if they add phase monitors.

  4. #4
    Join Date
    Apr 2003
    Location
    St. Louis
    Posts
    1,269
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    Phase monitor to ems to shut down all equip and call you.

  5. #5
    Join Date
    Jun 2019
    Location
    So Cal
    Posts
    375
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    Thread Starter
    Quote Originally Posted by servicefitter View Post
    Phase monitor to ems to shut down all equip and call you.
    Thank you sir, i have relayed your message as if it were my idea to the boss man. If he likes it ill give you credit

  6. #6
    Join Date
    Jul 2018
    Location
    Wisconsin
    Posts
    1,095
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    Good luck. Some dont see the benefit of a few hundred in parts and a few hours time, possibly saving them thousands in repairs down the road . Same goes with hail guards rarely see them but see coils beat to hell every day.

    Sent from my SM-G960U using Tapatalk

  7. #7
    Join Date
    Jun 2019
    Location
    So Cal
    Posts
    375
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    Thread Starter
    Quote Originally Posted by Spitz View Post
    Good luck. Some dont see the benefit of a few hundred in parts and a few hours time, possibly saving them thousands in repairs down the road . Same goes with hail guards rarely see them but see coils beat to hell every day.

    Sent from my SM-G960U using Tapatalk
    Man you sure are right about that, never is there money for improvements but always money for repairs... smh

  8. #8
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    42,433
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    Quote Originally Posted by BuildingMech88 View Post
    Man you sure are right about that, never is there money for improvements but always money for repairs... smh
    Yeah... sadly, spreadsheets take precedence over common sense...
    One of those things...

    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

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