3 phase rotor resistance

Discussion in 'Homework Help' started by Feeder, Apr 21, 2008.

  1. Feeder

    Thread Starter New Member

    Apr 21, 2008
    Hi Im new here, I have a few questions that Im not sure on and was hoping I could get some help.

    Firstly how would increasing the rotor resistance of a 3 phase motor effect the running torque, starting torque and the maximum torque related to the speed.

    Also what effect would increasing the rotor resistance have on the rotor torque?

    Any help would be very much appreciated.
  2. Papabravo


    Feb 24, 2006
    The time constant of an RL circuit depends on the ratio of the inductance L to the resistance R. Increasing R for the same inductance makes the ratio smaller. Making the time constant smaller allows you to get current flowing into the coil faster which will increase torque. There is a catch -- isn't there always a catch? To get the required current to flow for the desired torque you may have to increase the voltage of the current supply.