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  1. #118
    Join Date
    Jul 2001
    Location
    VA
    Posts
    2,801
    I don't know about all that crap Joe....but dang man......quit grabbin bare wires!!!
    ___________________________________________


  2. #119
    Join Date
    Apr 2007
    Location
    Kaufman county, Texas
    Posts
    10,082
    I swollowed a penny, a nickle, and two dimes. Next week I will be invunerable!

  3. #120
    Join Date
    Apr 2004
    Location
    Des Plaines,IL
    Posts
    1,016
    Quote Originally Posted by slimwoodie View Post
    HuH ..???

    one leg to ground is ... 277 ...
    Unless the power coming in is B-phase grounded, then it is 480V to ground with "ONE" wire.
    Stuart
    Lack of airflow destroys compressors.

  4. #121
    Join Date
    Dec 2006
    Posts
    293
    Quote Originally Posted by BamaCool View Post
    I'm getting tired of trying to explain how 3 phase electricity works & I'm about to go to bed. So, let me try this.....Especially for Bustawrench.....According to you, and all your research on the net, if I have a motor that runs on 460v 3 phase, and I disconnect one of the lines, that motor will still run because the power fairy will make sure there is still 460v there, even though 1 of the legs that make up the voltage is no longer present. I hope you don't actually work on 3 phase equipment. I tried to be nice, but that comment you made "Wrong", just pissed me off. If you are actually a commercial tech, I strongly reccomend you learn more about 3 phase systems. If I'm wrong I'll say I'm wrong, but I can promise you, there is no way you can prove me wrong. As far as that other bull$$t you were talking....No, Ive never been in a conversation with you before, and won't be again.
    I read this forum to learn about things I've not run across before, and to help someone it I can. I'm sorry if I took this thread off subject, and unless there's a post I just can't turn my back on........................Over & out
    it wont run because it nees the 3rd phase,or the CURRENT. take a start cap out and what happens, motor may start but wont do jack. take a leg out of 3phase and you have the same thing.

  5. #122
    Join Date
    Jan 2003
    Location
    San Jose, Ca
    Posts
    2,089
    Quote Originally Posted by BamaCool View Post
    I'm getting tired of trying to explain how 3 phase electricity works & I'm about to go to bed. So, let me try this.....Especially for Bustawrench.....According to you, and all your research on the net, if I have a motor that runs on 460v 3 phase, and I disconnect one of the lines, that motor will still run because the power fairy will make sure there is still 460v there, even though 1 of the legs that make up the voltage is no longer present. I hope you don't actually work on 3 phase equipment. I tried to be nice, but that comment you made "Wrong", just pissed me off. If you are actually a commercial tech, I strongly reccomend you learn more about 3 phase systems. If I'm wrong I'll say I'm wrong, but I can promise you, there is no way you can prove me wrong. As far as that other bull$$t you were talking....No, Ive never been in a conversation with you before, and won't be again.
    I read this forum to learn about things I've not run across before, and to help someone it I can. I'm sorry if I took this thread off subject, and unless there's a post I just can't turn my back on........................Over & out
    Good God!! yes when you disconnect one phase from a running motor on 3 phase you will still have 460, but it will be only single phase. If the motor is turning and the overloads or fuses do not trip it will keep turning but the motor will over amp and let the smoke out it if it has any kind of load. It is not the voltage alone that makes the motor turn but the difference in phase angle,

    On 480 three phase power the voltage between A and B is 480 vac, B and C is 480, and C and A is 480. And A, B, Or C to ground or neutral is 277 vac.

    Out of curosity if you think it is voltage that keeps a motor turning, what happens to the speed of a 208 vac induction motor when hooked up to 480?
    Old snipes don't die they just loose their steam

  6. #123
    Join Date
    Jan 2007
    Location
    Charm City--the city that bleeds
    Posts
    2,790
    No, and I don't want to be. (in answer to OP)

    I have bumped one leg of it as I was reconnecting the LV side of a compressor contactor.

    Also, I probably drive newbies crazy because I always tell them the following story as I go on and on about checking for voltage even if you are the one who disconnected the power, or no matter how much you think you trust someone who disconnected it.

    I was replacing a blower motor on an old 48DR (RTU) and I shut off at the disconnect, climbed on top after removing panels and proceeded to replace the motor.
    Almost ready to start it up, I checked in electrical panel and for some reason my meter told me that there was at least 260 to gnd. !!??

    The disconnect had broken and one of the knifes was not turning with the handle--it was stuck in the hot side.

    So I say ALWAYS check for power even after you disconnect.

    One more story to drive y'all nuts--
    brand new Lennox RTU with sectra system. One zone controller giving us problems. Shut off power and replaced controller. Now, nothing is working right. Come to find out the brand new disconnect did not disconnect, as it repeated this action in subsequent trials, and the 3000$ controller in the RTU was toast. Still had 160V to ground on one leg, and the OCC lamp was lit .

    Had enough? There was this one time....
    It's great to be alive and pumping oxygen!

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