Wiring two speed 6 wire 3 phase motor

Discussion in 'ELECTRICAL ISSUES - POWER YOUR MACHINES & SHOP' started by CanFire, Aug 27, 2013.

  1. CanFire

    CanFire New Member

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    I think I have this right, but it's always best to check before applying power. I am trying to wire up a two speed 6 wire 3 phase motor to run at it's highest speed.
    Below is the motor data plate and what's left of the wiring diagram.
    I believe I need to wire U1, V1, W1 to power and leave U2, V2, W2 disconnected. Please let me know if I'm right or wrong.
    Also, for programming the VFD, the highest speed setting would mean using 2 pole, 4.3 amps, and 1720 RPM?
    [​IMG]
    [​IMG]

    Thanks !
     
  2. DMS

    DMS Active Members Active Member

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    I think it's actually the diagram on the left, and you want to tie U1, V1, W1 together, and connect power to U2, V2, W2.
     
  3. CanFire

    CanFire New Member

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    Thanks. I've been doing more searching and I think you're right. Given the application as the power X Feed motor, I assume it's a constant torque 2 speed motor instead of constant power or variable torque configuration.
    I found this diagram for Constant Torque Dahlander Motors:
    [​IMG]
    Speed...Line......Short
    High.....4,5,6......1,2,3
    Low......1,2,3




    Do you have any idea what the 2(4)P and 4(8)P are supposed to indicate?
     
  4. DMS

    DMS Active Members Active Member

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    I think that is 2 pole/4 pole; not sure what the numbers in parenthesis mean though.
     
  5. twstoerzinger

    twstoerzinger Active Members Supporter Active Member

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    I am clueless on the "2(4)P" nomenclature, but 1720 rpm is 4 pole motor speed (1800 synchronous at 60 Hz).
    The motor nameplate shows both a 4 pole and what looks like "8" pole for the two speed options.
    The one speed is stamped 17xx which makes sense for 4 pole connection.
    The other speed stamp is hard to read, but looks to be 3 digits. 8 pole speed would be something a little less than 900 rpm.

    So if you are going for the highest speed, connect for 4 pole and program the VFD for 1720 rpm (or whatever that actually is on the nameplate).
    The nameplate gives two current draws, presumable one for each pole connection. I'm not smart enough to tell you wich current goes with which pole connection.

    Perhaps one of the motor wizards on the forum can tell you where to set the Full Load Current on the VFD.

    Terry S.
     
  6. jamie76x

    jamie76x Active Members Supporter Active Member

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    I had the same exact motor on a ramco mill. I could not find a switch easily so I wired it just on the high rpm and had no issues. Before the switch went it sure was nice having 2 speeds.... Just wire it to the diagram to the right and you will be set.
     
  7. CanFire

    CanFire New Member

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    It's almost as hard to read the motor data plate in real life as it is in the picture, but I believe it says...

    HP: 1 - 1/2 (meaning 1hp or 1/2hp depending on how it's wired for speed?)
    Pole: 4 / 2 (although reversed order, might correspond to the 2(4)P and the 4(8)P wiring diagrams)
    RPM: 1720
    RPM: 860
     
  8. rdhem2

    rdhem2 Active Members Active Member

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    The Gentleman is correct. 2P-3600rpm, 4P-1800 rpm, 6P-1200rpm and so on. Formula--120 x Frequency / # of poles = SPEED. The 3450 and 1750 and 1125 numbers refer to more of a true generated speed allowing for slip, bearing friction, efficiency etc.

    The easy way to get your two speed back is to purchase a two speed starter. Then you install a three position selector LOW OFF HIGH and you are in business. Sure is a nice feature to let go unused. You are also then able to install the correct overload protection for each speed.

    You are correct as to the HP ratings. I don't fully understand the meaning of the numbers either as the speeds indicate a 4 and 8 pole winding arrangement.

    Name plate indicates 4.2amps as the max for high speed.
     
    Last edited: Aug 28, 2013
  9. CanFire

    CanFire New Member

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    :winner:
    I just wired it up both ways for testing and you were right.

    My thanks to everyone who replied !
     
  10. DMS

    DMS Active Members Active Member

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    I love it when I'm right ;)
     

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