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Thread: 6 Lead Motor Connection

  1. #1
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    6 Lead Motor Connection

    I have a 200hp 4.16/2300V 6-Lead motor I need termination information for. This motor is going on a 4.16kV system and I'm not sure weather I should connect it in a wye or Delta fashion?

    I always thought wye was for wye-delta starting and most motors were always connected delta but I'm not sure in this case. Any advice?

  2. #2
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    With a 6 lead, dual voltage motor, you connect it in wye for the higher voltage and in delta for the lower voltage. In this case your motor will have windings rated at 2300 volts and when connected in delta to a 2300 volt source each winding will see its rated voltage. When you connect the motor in a wye for the higher voltage each winding will see the supply voltage divided by the square root of 3. 4160/square root of 3 = 2400 volts.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  3. #3
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    Quote Originally Posted by don_resqcapt19 View Post
    With a 6 lead, dual voltage motor, you connect it in wye for the higher voltage and in delta for the lower voltage. In this case your motor will have windings rated at 2300 volts and when connected in delta to a 2300 volt source each winding will see its rated voltage. When you connect the motor in a wye for the higher voltage each winding will see the supply voltage divided by the square root of 3. 4160/square root of 3 = 2400 volts.
    Don,

    I would like to live inside your brain for 30 days
    Bottom line: if you are doing this for money, do it right or walk away.

  4. #4
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    Quote Originally Posted by don_resqcapt19 View Post
    With a 6 lead, dual voltage motor, you connect it in wye for the higher voltage and in delta for the lower voltage. In this case your motor will have windings rated at 2300 volts and when connected in delta to a 2300 volt source each winding will see its rated voltage. When you connect the motor in a wye for the higher voltage each winding will see the supply voltage divided by the square root of 3. 4160/square root of 3 = 2400 volts.
    O.K. so it looks like the answer is to wire it in the "wye" configuration so that the windings will see 2400V which is close to the rating of 2300V.

  5. #5
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    Quote Originally Posted by Pitt123 View Post
    O.K. so it looks like the answer is to wire it in the "wye" configuration so that the windings will see 2400V which is close to the rating of 2300V.
    And, regarding your "I always thought wye was for wye-delta starting", that is also true, but with THIS motor, that would be done only on a 2400 supply. The wye connection starts a "4160" motor on "2400" reducing torque and inrush current.

  6. #6
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    Quote Originally Posted by Pitt123 View Post
    O.K. so it looks like the answer is to wire it in the "wye" configuration so that the windings will see 2400V which is close to the rating of 2300V.
    Yes...the motor nameplate really should read 4.16kv/2.4kv. I don't know why it says 2300 volts.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  7. #7
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    Quote Originally Posted by don_resqcapt19 View Post
    Yes...the motor nameplate really should read 4.16kv/2.4kv. I don't know why it says 2300 volts.
    Should this be a cause for concern?

  8. #8
    The way I read the original question is similar to a comment I just made in another thread. Some people confuse the configuration of the internal windings of the motor with how it should be connected to supply power. Even if the motor is configured as wye connected, it does not mean it should be connected as wye to the power supply. The wye configuration is internal to the motor only, and it should not be connected to the grounded conductor of the supply power. Doing otherwise can result in unbalanced currents in the windings.

  9. #9
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    Quote Originally Posted by Pitt123 View Post
    Should this be a cause for concern?
    No...it is not an issue. I just find it strange that they used those numbers as that combination of voltages is not possible.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  10. #10
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    Quote Originally Posted by don_resqcapt19 View Post
    Yes...the motor nameplate really should read 4.16kv/2.4kv. I don't know why it says 2300 volts.
    For the same reason 120v motors say 115v, 240's say 230v, etc.?
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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