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Question Details:
Hey, just a quick question.
Theres 2 questions here;
A 75-kW, 3-phase, 440-V (line to line), 4-pole, 60 Hz Y-connected
induction motor. Given that, stator iron loss is 2kW, windage and friction losses
are 1.2kW and resistance between two stator terminals = 0.4W, for slip s=0.05,
mechanical power supplied to the load PL=41.5 kW and Motor efficiency h =82%;
Calculate: Line current drawn from the supply
Solution:
Pcu-stator=3.66kW=3I2Rs (note for Y connection IL=Iph; Rs=0.4/2)
⇒ I = 78A
and
A
75-kW, 3-phase, 440-V (line to line), 4-pole, 50 Hz
Y-connected induction motor. Given that, stator iron loss is 2kW,
windage and friction losses are 1.2kW and the per phase resistance of
stator winding = 0.18W, for slip
s=0.05, mechanical power supplied to the load PL=41.5 kW and Motor
efficiency  =83%; Calculate:
Calculate: Line current drawn from the supply
Solution: Pcu-stator=3.05kW=3I2Rs (note for Y connection IL=Iph; Rs=0.18)
⇒ I = 75.15A
So my questions is: "Why do you divide Rs by 2, for the first question,
and not the second questoin" Thats all, please help, thanks :)
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