Nameplate rating current of a 3 phase motor

Discussion in 'The Projects Forum' started by maheshaprasad, Nov 27, 2009.

  1. maheshaprasad

    Thread Starter New Member

    Nov 25, 2009
    For a 3 phase delta connected induction motor, the name plate current rating means what?
    the line current it draws from the source or the phase current circulating inside the winding in the full load conditions.

    And the overload protection should be selected according to which one.
  2. Duane P Wetick

    Active Member

    Apr 23, 2009
    Normally, the nameplate current rating is the amount of line current drawn from the source when the motor is running at full horsepower load. Typically the line current will be less, if the motor is not fully loaded. With no load on the motor, the current will be much less than the nameplate rating. For 3 phase motors, a rule of thumb for calculating currents is HP x 746 / VAC x efficiency (.86 typ.). Overloads should be selected according to the duty or class of operation the motor will be subjected to.

    Cheers, DPW [ Spent years making heaters out of op-amps.]

    Senior Member

    Jul 1, 2008
    May I ask what the HP rating is and what you're going to drive?
  4. maheshaprasad

    Thread Starter New Member

    Nov 25, 2009
    Thanks Duane,

    I got my answer that the nameplate rating is the Line current.


    This was a very generalised question not meant for any specific application. anyways thanks for showing intrest in my post.