the label values of the 3-phase asynchronous motor are; 380V, 5A, 50Hz power factor; 0.8, 1.9kW. what is the efficiency of this engine at full load

In a factory, the following are the loads: Induction motors: 90 hp. 0.7 power factor. 0.82 efficiency Lighting and heating: 10 kW Synchronous motor: 20 kVA unity power factor a) Determine the overal power factor of the factory loads b) To improve the the factory power factor. the synchronous motor is overexcited without any change in its load. Determine the VAr that must be injected by the synchronous motor to raise the overall power factor of the factory to 0.9. 1 hp =746 W

7. A 3 MVA, 6 pole alternator runs at 1000 rpm on 3.3 kVolt bus-bars. The synchronous reactance is 25%. Calculate the synchronizing power and torque per mechanical degree of displacement when alternator is supplying full-load at 0.80 power factor. Ans. Psy=722.43 kW and Tsy = 6,900 N-m

A 400V, 50Hz 30hp three-phase induction motor is drawing  current at  power factor 0.8 lagging. The stator and rotor copper losses are 1.5kW and 900W respectively. The friction and windage losses are 1050W and the core losses are 1200W . Find the air-gap power of the motor.

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2.. A three-phase 60 Hz asynchronous motor runs at 890 rpm at idle and 840 rpm at full load. ww w w www wwww a) How many poles does this motor have? b) What will be thę slip at nominal load? c) What happens if the nominal load is slipping at half? www. d) What is the electrical frequency of the rotor at half the nominal load? wwww

A certain 60Hz, four-pole split-phase induction motor spins at 1760rpm when running with no torque load. Find its slip at no load. A. 1800rpm C. 1150rpmB. 90rpm D. 40rpm

(Qld) A three-phase 20-pole induction motor is rated at 800 V, 50 Hz. What is the synchronous speed of this machine if the voltage at its terminals is reduced to 400 V (a) 150 rpm, (b) 300 rpm, (c) 600 rpm, (d) 3000 rpm

B. Open-Ended Question 6. A 45 hp, 50 Hz, 415 V delta connected induction motor has a full load efficiency of 0.80 and p.f0.60. The p.f is to be improved to 0.9 using static capacitors. Determine (i) rating of capacitor bank kVAR, (ii) capacitance of each unit, if they connected as (a) delta, and (b) star, in uF. 7. Figure 1 shows the electrical power system with rated capacity of S₁= S₂=25 MVA, connected with two step-up transformers 11 kV/66 kV, respectively. The short circuit fault at point 'p' occurs at the outlet of transmission line. Calculate the short circuit current and three phase short circuit capacity occur at the point 'p'. S₂=25 MVA G₁ % Xg1 = 30 T₁ % XT1= 5 Transmission line 11/66 kVA S₂=25 MVA T₂ CB ~) G₂ % Xg2 = 30 % XT2 = 8 11/66 kVA

The figure below shows the per-phase equivalent circuit, referred to the stator. of a 400V. 50 Hz. four-pole, star-connected, wound-rotor, three-phase induction motor. What is the ratio of motor maximum torque to starting torque? j120 0.54 Ω. j 0.56 Ω E mm. 27.0 0.43/50