1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Three phase induction motors

  1. Jun 1, 2008 #1
    hey does anyone know the effiency and power factor of a typical three phase induction motor?

    Last edited: Jun 1, 2008
  2. jcsd
  3. Jun 1, 2008 #2
    Well, it's always a good thing to start off with the definitions of efficiency, power, and power factor.

    Let [tex]\eta[/tex] be the efficiency, then [tex]\eta = \frac{P_{out}}{P_{in}}[/tex]
    Let P= power, then P=VI.

    Therefore the average Power = [tex]VIcos(\theta) [/tex]
    By definition of power factor, it is the ratio of average power/VI.
    Thus, the definition of power factor = [tex]\frac{VIcos(\theta)}{VI}=cos(\theta)[/tex]

    From here, use the Pythagorean theorem to solve for power factor of a three phase
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Three phase induction motors
  1. Three phase system (Replies: 1)