Question about Induction Motors

Discussion in 'Homework Help' started by Durzo972, Nov 24, 2012.

  1. Durzo972

    Thread Starter New Member

    Nov 16, 2012

    Just did a lab involving induction motors. I am just wondering about variables and parameter that affect the speed of the rotor. Are the variables current and voltage and parameter is the torque? Thanks
  2. BillB3857

    Senior Member

    Feb 28, 2009
    Primary function is frequency. For 60Hz, it is not uncommon to see motors rated at 1750 RPM. Synchronous speed would be 1800 for that motor so the 50RPM drop is called slip resulting from load. If you think about how an induction motor is made, the slip allows the synchronous speed rotation of the field to cut through the shorting bars of the rotor which in turn, generate the armature field and torque. Others will clarify and correct my attempt to explain.
  3. shortbus

    AAC Fanatic!

    Sep 30, 2009
    BillB - that is true in the case of a four pole motor, but other numbers of poles have other "base" speeds. Two pole motors are higher RPM, and more than four pole motors have lower RPM. Then you get into changing speed by changing AC frequency.
  4. BillB3857

    Senior Member

    Feb 28, 2009
    Right, Shortbus! I should have included the base design of the motor. My primary focus was on the external influences.