A 2 hp three phase delta connected motor operates at a power factor of 0.8 (lagging). The motor has an efficiency of 82%. If the motor is connected to a 3 phase supply of line to line voltage of 400 V, calculate the line current and phase current of the motor.

A 2 hp three phase delta connected motor operates at a power factor of 0.8  (lagging).  The  motor  has  an  efficiency  of  82%.  If  the  motor  is  connected  to  a  3  phase  supply of line to line voltage of 400 V, calculate the line current and phase current of the motor.

Solution:

Output power of the motor (mechanical), Pout= 2 hp = 2 x 746 W = 1492 W

Efficiency, η= 0.82

So, input power (electrical), Pin= P = Pout / η= 1819.5 W

Power factor, cosθ= 0.8

Now,  P = √3V_L I_L cosθ

I_L = P/√3V_L cosθ  = 1819.5/√3x400x0.8 = 3.28A

For a delta connected system, I_{p =}  I_L/√3 = 1.9A

EEE Job Math-2

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