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  1. #1
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    Delta connection



    Good day Engineers
    Please I need urgent help.
    I'm not that grounded in electrical.

    I connected a compressor today and the result was a blast.. Breakers trip and compressor burnt.
    The compressor was rewound while the 6 terminals connected with jumpers.
    Thus making it 3 lines to connect the 3 phase.

    My question is that can I connect the 3 phase from any side of the jumpers. That is either from 1, 2, 3 or 7, 8, 9



  2. #2
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    Re: Delta connection

    Brian - Newton Abbot, Devon, UK
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    Re: Delta connection

    If compressor is burnt than that mean it was wrongly connected in first time. Give us picture of compressor nameplate and give us data of Nigerian voltages of 3 phase system. Then we will be able to help you to correctly connect compressor. Do not connect it in current jumper configuration since it will probably burn again!

    As I can see, your country have 400V 3 phase system.
    If motor nameplate say 230Δ/400Y than it could be connected only in star winding configuration, and delta is not option for your country, except if you using frequency inverter configured to run with 230V.

    Induction-motor-winding-terminals-connected-in-star-and-delta-configuration.jpg

    In your country you can use delta configuration only with motors rated to run delta on 400V (400Δ/400Y or 400Δ/690Y)
    Last edited by nike123; 18-12-2018 at 09:59 PM.

  4. #4
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    Re: Delta connection

    Thanks a lot Mr. Nike.
    Going with your clear explanation, which says L1 to U1, L2 to V1, L3 to W1... What will happen if I mistakenly connect L1 to W2, L2 to U2 and L3 to V2.
    Referring to your Delta Connection Diagrams.

    Thanks

  5. #5
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    Re: Delta connection

    As U1 is linked out to W2 it does not really matter which terminal you connect L1 onto. It is just conventional to connect onto U1, V1 and W1.
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  6. #6
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    Re: Delta connection

    Thanks hyperion

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    Re: Delta connection

    Quote Originally Posted by OkonedoCharles View Post
    Referring to your Delta Connection Diagrams.
    I think you missing point of my post which is reason why your motor is burnt in first place. I am not sure that you can connect your motor in delta configuration.

    But if you asking in general, than it makes no difference from which side of delta connection you supply power (U1,V1,W1 OR U2,V2,W2) as Hyperion already explained.
    Last edited by nike123; 19-12-2018 at 06:19 PM.

  8. #8
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    Re: Delta connection

    Thanks Mr. Nike!
    I got you. Though the connection I did was right, yet the Carlyle compressor winding got shortened to body.
    Again the ways the coils read to each other got me confused.
    Considering the terminal, T1, T2 and T3 all read to each other ( resistance), while T7 T8 and T9 also read continuity.
    Jumpers were used to link T1 to T7, T2 to T8, and T3 to T9.
    I was not expecting T1, T2 and T3 to read continuity, likewise T7, T8, T8.

  9. #9
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    Re: Delta connection

    Let us start again, this time from the motor starter.

    How is the motor started?

    Is it direct on line, star/delta, part wind ?
    Brian - Newton Abbot, Devon, UK
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    Re: Delta connection

    By numbers mentioned (T1-T3, T7-T9) It is probably part winding motor! Where are T4-T6?
    That is why I asked first to:"Give us picture of compressor nameplate"!

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    Re: Delta connection

    Direct on line

  12. #12
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    Re: Delta connection

    Quote Originally Posted by nike123 View Post
    By numbers mentioned (T1-T3, T7-T9) It is probably part winding motor! Where are T4-T6?
    That is why I asked first to:"Give us picture of compressor nameplate"!
    IMG_20181218_115138.jpgIMG_20181218_115138.jpgIMG_20181218_115138.jpgIMG_20181218_115138.jpgIMG_20181218_115138.jpg

  13. #13
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    Re: Delta connection

    Here is a link to the 06E service Manual.
    https://www.utcccs-cdn.com/hvac/docs...06/020-611.pdf
    Electrical connections start around page 108

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    Re: Delta connection

    Thanks a lot Mr. Frank

  16. #16
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    Re: Delta connection

    Hi looking at the compressor photo, it is a 50% part wind and your wiring is OK, I think it might be a problem with the stator or the rotor bars

  17. #17
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    Re: Delta connection

    Quote Originally Posted by GHAZ View Post
    Hi looking at the compressor photo, it is a 50% part wind and your wiring is OK, I think it might be a problem with the stator or the rotor bars
    Can you please explain how it is a part wind with the wiring scheme shown.
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    Re: Delta connection

    Hi Brian!
    According to nameplate picture, motor is internally connected in star (or delta) configuration and cannot be in field modified.
    When connected 3 wire +PE with bridges, it is direct on-line start (2 windings in parallel => 100% starting current).
    When connected with 6 wires +PE without bridges, than it is part winding. In that case 2 contactors are used with one with time delay at start (1 separate winding at start for time delay => 50% starting current).

    As OP stated earlier, it was bridged as in picture at right side of motor nameplate which is direct on-line connection.

    But we still don't have full model number to verify correct voltage is applied. If compressor previously worked in Nigeria on direct line voltage, than it is probably of correct voltage.

    Screenshot_20181222_020634.jpg

    All that above said is under presumption that motor rewinding is done exactly as original is wounded in the factoy.
    Last edited by nike123; 22-12-2018 at 01:20 PM.

  19. #19
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    Re: Delta connection

    How about a photo of the contactor(s)

  20. #20
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    Re: Delta connection

    Thanks Nike, I do understand the part wind scheme but was asking because the OP stated it was a DoL starter and I couldn't see how part wind could be applied that way.
    Brian - Newton Abbot, Devon, UK
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