Xformers week 3

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The flashcards below were created by user harlanjr on FreezingBlue Flashcards.


  1. how many coils away is the power leg from the neutral bushing of the lighter transformer
    1 1/2
  2. the lighter transformer has a ______ KVA rating than the power pot
    larger
  3. the lighting transformer supplies the  _______ of the single phase load and half of the three phase load
    majority
  4. what is the voltage form the power leg to the neutral of the lighting transformer
    208
  5. what is the voltage from the power leg to any hot leg on the lighting transformer
    240
  6. if you accidentally connect the power leg to a hot leg at the customer's serice, what could be the consequences
    damage 120v electrical appliances
  7. if the primary coil voltage of a transformer is the same as the phase to phase voltage of system the transformer will be connected wye or delta
    delta (system voltage)
  8. how many primary phases are required to connect open wye primary to provide three phase open delta secondary
    2
  9. can open wye secondary provide three phase power using two transformers
    no
  10. can you get 3 phase 120/208 from an open delta bank? what is the three phase voltage from an open delta bank on the secondary side
    no; 120/240, 240/480
  11. can two or three single phase transformers be connected to supply three phase service
    yes
  12. if the primary side of two transformers are connected to two phases and a neutral, is this a wye or delta connection
    wye
  13. can you get three phases secondary using two phases of the primary? how would that primary connection be configured, wye or delta
    yes; wye
  14. how do you swap rotation on three phase transformer
    swap 2 hot legs on the lighting transformer
  15. how many phases are required on the primary side of an open delta/open delta bank
    3
  16. how will the secondary on a 2 pot bank always be hooked up
    delta
  17. what is an open bank
    two transformers banked together to supply 3 phase secondary power; one leg of the delta or wye configuration is gone or open
  18. how many phases does it require to to deliver proper output voltages on a open delta primary connection
    3
  19. how many phases does it require to deliver proper output voltages on a open wye primary connection
    2
  20. open banks are only ____ as efficient as closed banks (closed banks have 2 transformers
    57.7%
  21. how do you connect the primary on an open bank delta
    • transformer 1 - H1 to A phase, H2 to B phase
    • transformer 2 - H1 to B phase, H2 to C phase
  22. how do you connect the primary connections on a open bank wye
    • transformer 1 - H1 connects to A phase, H2 to neutral 
    • transformer 2 - H1 connects to B phase, H2 to neutral
  23. how do you connect the secondary on open bank wye and delta (subtractive transformer)
    • lighter transformer - X1 to phase, X2 to neutral, X3 to to X1 on power transformer
    • power transformer - X1 to X3 of lighting transformer, X2 open, X3 to power leg

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Author:
 harlanjr
ID:
 262941
Filename:
 Xformers week 3
Updated:
2014-02-20 13:42:59
Tags:
Xformers week
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Xformers week 3
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