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3 Phase Induction Motor Full Load Power Factor

  1. Jan 30, 2015 #1
    Hi, If the voltage, full load current and full load output power (kW) of a 3 phase induction motor are known, and the efficiency is assumed to be 90% (is this realistic), am I correct in thinking that the full load power factor can be approximated (due to assumed and not actual efficiency) as follows;

    P.F. = Output Power/(√3 * VLine*ILine*Efficiency)

    E.g. Is the approximate full load power factor obtained by the Full Load Output Power (Mechanical Watts) divided by the full load kVA * Efficiency?
  2. jcsd
  3. Jan 30, 2015 #2
    Let's see:
    Pout = Pin x Eff => Pin = Pout / Eff

    PF = Pin / (sqrt(3) x VA)

    PF = Pout / (sqrt(3) x VA x Eff)

    Looks good.
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