synchronous motor is needed so that the overall power factor is 85% lagging. 2. A 400 V three-phase balanced load takes 50 A at a lagging power factor of 0.707. An over-excited synchronous motor is connected to improve the power factor to unity. If the mechanical output of the synchronous motor is 20 HP and its efficiency is 82%, find the required KVAR and operating power factor of the synchronous motor under this condition.

A three phase 250 hp induction motor operates at 0.8 lagging power factor on 440 V, 50 Hz supply. The full load efficiency of motor is 70 %. It is required to improve the power factor to 0.95 lagging by using the capacitor bank connected in delta. Find current through capacitor.

A 50 Hz, 3-phase induction motor is working at a full load speed of 1440 r.p.m. The full load slip will be

In a closed cycle gas turbine, there is two stage compressor and two-stage turbine. All the components are mounted on the same shaft. The pressure and temperature of air at inlet to the first stage compressor are 1.5 bar and 20°C respectively. The maximum cycle pressure and temperature are limited to 750°C and 6 bar. A perfect intercooling and reheating are used between the compressors and the turbines. A regenerator whose effectiveness is 0.7 was employed. Assuming the compressors and turbines efficiencies as 0.82, calculate: a. Thermal efficiency of the cycle. b. Mass of working fluid for a power output of 350 kW. Assume the working fluid is air has Cp = 1.005 kJ/kg K, y = 1.4.

When 40V DC voltage is applied to a single-phase AC motor, it draws 1A current. When 200v-50Hz AC is applied to the same motor, it draws 4A current. Calculate the capacity of the capacitor to be connected in parallel and the circuit current in this case to make the power factor of this motor 0.9.

Permanent-split capacitor motor is in effect a 2-phase motor and at no load could attain the synchronous speed. True False

5. An inductive load consumes 10kW at 0.75 PF lagging. A synchronous motor with a pf of 0.9 leading is connected in parallel with the inductive load. What is the minimum required kW size of the synchronous motor so that the combined load will have a pf of 0.8 lagging.

4. A Factory takes 200-kW at 1100-volts from a trhee-phase supply and the power factor and the power factoris 0.71 lagging. A synchronous motor is installed which takes an additional 100-kW. What must be the kVArating on this motor to raise the power factor of the system to (a) 0.87 lagging and (b) 0.9 lagging

V1 = 170 V f1 = 100 Hz 1) A single-phase load has an active power of P = 2 kW at V1 V @f1Hz and the power factor is cosφ = 0.75. This motor iscompensated to cosφ = 0.85 using a parallel capacitor Find the reactive power difference between compensated and uncompensated status (which will give the capacitor power) and calculate XC and C using the power difference value?

8A (L) DC SOurce Transformatlons 2A 31U Compute lo