Question 11: (3 marks) A 6 pole, 60 Hz, star connected three-phase induction motor has a rating of Pm = 55 kW and line voltage = 420 V. The slip of the motor is 2% at 0.9 power factor lagging. If the full load efficiency is 95%, calculate the torque developed in the motor.
Question 11: (3 marks) A 6 pole, 60 Hz, star connected three-phase induction motor has a...
4.6. A 460-V, 75 kW, 4-pole, delta-connected, 60-Hz, three- phase induction motor has a full-load slip of 5 percent, an efficiency of 92 percent and a power-factor of 0.87 lagging at full-load. At start-up, the motor develops 1.9 times the full load developed torque but draws 7.5 times the rated current at the rated voltage. This motor is to be started with an auto- transformer reduced-voltage starter. Assume the stator resistance and the stator core loss to be negligible. Calculate...
Question 2 (10 marks) (a) A large 3-phase, 4000 V, 60 Hz, slip of 0.01, squirrel cage induction motor draws a current of 375 A and a total active power of 2300 kW when operating at full-load. The stator is connected in wye and the resistance per phase is 0.05 12. The total iron losses are 23 kW and the windage and friction losses are 10 kW. Calculate the following: i) The power factor at full-load ii) The active power...
Question 2 (10 marks) (a) A large 3-phase, 4000 V, 60 Hz, slip of 0.01, squirrel cage induction motor draws a current of 375 A and a total active power of 2300 kW when operating at full-load. The stator is connected in wye and the resistance per phase is 0.05 12. The total iron losses are 23 kW and the windage and friction losses are 10 kW. Calculate the following: i) The power factor at full-load ii) The active power...
Question 2 [10 marks) A six pole, three phase induction motor, with a star connected stator winding is energised from a 380V, 50Hz supply. The ratio of the stator to rotor turns is assumed 1.8 and a full load slip of 4%. If the respective per phase rotor resistance and standstill reactance are 0.120 and 0.8502, determine: a. Torque developed at full load b. The maximum torque and the speed at maximum torque
3 phase, 37.3 Kw, 440 V, 50 Hz induction motor operates at full load with efficiency 89% and power factor 0.85 lagging. Calculate: A) The total KVA rating of capacitor required to rise full load power factor to 0.95 lagging. B) What is capacitance per phase if capacitor: 1) Delta connected. 2) Star connected.
A 1500-kVA, 6.6 kV, 50 Hz, 6-pole, three-phase, star-connected
synchronous generator has a resistance 0.5Q/phase and a synchronous
reactance of 5Q/phase. The generator is supplying its rated power
at its rated voltage and at a power factor lagging. The rotational
loss is 2 kW. Calculate:
(a) the power developed,
(b) the power angle,
(c) the voltage regulation, and
(d) the shaft torque.
A 1500-kVA, 6.6 kV, 50 Hz, 6-pole, three-phase, star-connected synchronous generator has a resistance 0.50/phase and a synchronous...
1. A 15 hp, 4 pole, 208 V, 60 Hz, Y-connected, three-phase squirrel cage induction motor has the following parameters in Ω/phase referred to the stator: R,-0.220, Xi = 0.430, X,-15.0, R2 0.130 and X2-0.430. Mechanical and core losses amount to 300 W and 200 W respectively for rated voltage. (a) The motor is fed with a 60 Hz, 208 V voltage. It runs with a slip of 4.5 %. Find the speed, shaft torque and power, efficiency and power...
A 4 phase, 460 V, 60 Hz, 26.8 hp, 4 pole, Y-connected
induction motor draws 25 A at a power factor of 0.9 lagging. Core
loss is 900 W, stator copper loss is 1100W, friction and winding
losses are 300 W, and stray loss is neglected. The machine shaft
rotates at 1738 rpm. Calculate the air gap power and output load
torque
- [Induction Motor - 15 points) A three-phase, 460 V, 60 Hz, 26.8 hp, 4-pole, Y-connected induction motor...
A 3-phase, 460 V, 1740 rpm, 60 Hz, 4-pole wound-rotor induction motor has the following parameters per phase: R1 = 0.25 Ω, ' 2R = 0.2Ω, ' 1 2 X = X = 0.5Ω, 30 m X = Ω. The rotational losses are 1700 W. With the rotor terminals short-circuited, find: 1. at starting: • current when started direct on full voltage, • a torque 2. at full load: • slip • current • ratio of starting current to full-load...
Problem 3: Consider an 6 pole 3-phase AC induction motor being driven at 60 Hz a) b) c) d) When connected to a load, the motor outputs 2 kW of power assuming negligible rotational losses while rotating at a speed of 1070 rpm. What is the slip? (5 points) When connected to a load, the motor outputs 2 kW of power assuming negligible rotational losses while rotating at a speed of 1070 rpm. What is the developed torque? (5 points)...