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  1. #14
    Join Date
    Dec 2006
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    Middle Tennessee
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    when the grounded motor(s) get fixed rest will run correctly!



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  2. #15
    punch.... whack... zap....krunch... pow...oof.... OK ... enough now.... I thought the person might have been looking at a 480 volt unit and that they were talking about a single phase 277 single phase fan motor.... that said... the "no such thing" remark was wrong to the extent that single phase motors that go on those units are as far as I know are rated "440 volt" if they are single phase.... or I could be wrong.............

  3. #16
    Join Date
    Dec 2001
    Location
    Chicago, N/W burbs
    Posts
    8,004
    I see 460 1/ph motors all the time.
    R2B4BTU

  4. #17
    Join Date
    Feb 2007
    Location
    Dallas, Tx.
    Posts
    575
    grounded motor. the others are backfeeding their constant hot leg back to ground at the grounded motor. 1 leg to ground = 277v. and that is what the other motors are slowly spinning on.
    mike

  5. #18
    Join Date
    Dec 2006
    Location
    Middle Tennessee
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    Quote Originally Posted by coronado2412 View Post
    I thought the person might have been looking at a 480 volt unit and that they were talking about a single phase 277single phase fan motor, that said, the "no such thing" remark was wrong to the extent that single phase motors that go on those units are as far as I know are rated "440 volt" if they are single phase, or I could be wrong


    bamm, hammertime, wrong they are rated at 460 volts!

    never seen a 277 single phase condenser fan motor either!



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  6. #19
    Join Date
    Mar 2007
    Location
    Houston, Texas
    Posts
    157
    check fan capacitor of each OFM

    Quote Originally Posted by addison View Post
    Hello to all I have a 30 ton RTU Lennox unit thats about 9 years old. Its been a good unit till now. I got a call for a lack of cooling from the unit,what I found was that it was tripped out on High Pressure, the whole unit!!. After I reset it.
    I found 1 fan locked up 1 not running and the other 4 running about half the speed they normally due (these are single speed fans) they are 480VAC single phase 1/3 hp motors. I could not dive into it because of a heavy rainstrom thats still dumping and its been 4 hrs and its not letting up. I would appreciated any words of wisdom on the matter(this is something that I have never seen before). Thanks Addison Ft Worth Texas

  7. #20
    Join Date
    Jun 2005
    Location
    The Gray Northwest
    Posts
    661
    Quote Originally Posted by coronado2412 View Post
    No such thing as 480 volt single phase.... 480 to neutral is 277 VAC which is single phase................ slow turning motors?........ start at the capacitor... a PSC with a bad...er open cap will run only on the run winding..... a motor running in a single winding is called a split phase.... which my guess is not what you have for fan motors............
    Got a bunch of Carrier GQ30 heat pump chillers w/460 single phase condenser fan motors.

  8. #21
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,532
    Quote Originally Posted by hvaccop View Post
    460 between two hot legs
    i have seen some other things between 2 hot legs!

    sorry, i couldn't resist.
    "If you pull one more stunt like you just pulled with Tommy, you won't have to get on a plane because I will personally kick your ass from here to Korea!" - Best of the Best

  9. #22
    Join Date
    Dec 2006
    Location
    Middle Tennessee
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    Quote Originally Posted by jayguy View Post
    i have seen some other things between 2 hot legs! sorry, i couldn't resist.


    after a few beers get very close to the 2 hot legs and then



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  10. #23
    Join Date
    Mar 2007
    Location
    Central Oregon, paradise on earth
    Posts
    820
    If you're reading off a leg that the run capacitor is on, you can get weird readings. Probably not the case, but just thought I'd say it anyway. IF it's running at the time you measure.
    I believe in latent heat.

  11. #24
    Join Date
    Apr 2003
    Posts
    33
    After The Rain stopped I found 2 blown fuses and 2 bad run caps,
    And Yes this is a 480volt 3ph unit with 6 ODFs that are 480 vac 1ph
    277 across each leg makes it a 480 volt single phase motor. End Of story>

  12. #25
    Join Date
    Nov 2003
    Location
    Boston
    Posts
    600
    Quote Originally Posted by Airmechanical View Post
    bamm, hammertime, wrong they are rated at 460 volts!

    never seen a 277 single phase condenser fan motor either!



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    I've had to change out a 277 volt compressor on a Leibert MiniMate ceiling mount unit.

    It took the feed from the Lighting Circuit.

    Special order, too. 3 week lead time.

    Can't remember but the fans must have been 277 also.
    Edited by powerhead on more than one occasion

  13. #26
    Join Date
    Dec 2006
    Location
    Middle Tennessee
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    Quote Originally Posted by powerhead View Post
    I've had to change out a 277 volt compressor on a Leibert MiniMate ceiling mount unit.

    It took the feed from the Lighting Circuit.

    Special order, too. 3 week lead time.

    Can't remember but the fans must have been 277 also.
    thats why i stated i never seen, leibert is some badass equip. and thats why i did not state there is no such thing.

    i bet that was fun changing that compressor up there!

    why would ya feed from a lighting circuit?



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