shaunt dc motor

Discussion in 'Homework Help' started by qwerty321, May 8, 2012.

  1. qwerty321

    Thread Starter Member

    Oct 22, 2008
    14
    0
    Hello, I have this small problem in which I need some help:

    An 8- hp, 220- V, 3000- rpm shunt dc motor has a rated efficiency of 85% with a rated current of 0.3A in the shunt field winding. What is the armature resistance of this motor?
    (0.819Ω is the answer but I don't know how to get it.

    I am trying to relate the efficiecny to the losses which include (RF*IF+Ra*IA) but cannot get the result
    Thank you for the help
     
  2. qwerty321

    Thread Starter Member

    Oct 22, 2008
    14
    0
    please help i have an exam tomorrow:(
     
  3. qwerty321

    Thread Starter Member

    Oct 22, 2008
    14
    0
    HELPP please!
     
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