Name: 23. A 3-phase, 5000 hp, 6000 v,60 Hz, 12-pole wound-rotor induction motor has the 1, resistance between stator terminals-o12 Ω 2. resistance between rotor slip-rings-0.0073 Ω 3. windage and...
Consider a 50 kW, 3-phase, 380 V line-to-line, 50 Hz, 6 pole Y-connected wound-rotor induction motor. The stator winding ac resistance is 0.1 Ω/phase. The effective stator-to-rotor turns ratio is 2. The exciting branch is negligible. It is found that when an external resistor of 0.09 Ω/phase is connected to the rotor terminals maximum starting torque of 1150 Nm is obtained. a. Compute the internal mechanical power and the internal torque developed by this motor when it drives a load...
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...
A 500 hp, three-phase, 2200 V, 60 Hz, 12-pole, Y-connected, wound-rotor induction motor has the following parameters: 5.9 0.225 Ω x, R, R',-0.235 Ω X, 31.8 Ω R""-780 Ω 1.43 Ω Calculate the following: a. Slip at maximum torque b. Input current and power factor at maximum torque c. Maximum torque d. Resistance that must be added to the rotor windings (per phase) to achieve maximum torque at starting
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...
The input power to a 480V, 3 phase, 6 pole, 50 Hz induction motor is 75kW with a line current of 75A and runs at a slip of 2.5%. If the stator core loss is 2 kW, windage and friction loss is 1.2 kW, and the stator resistance per phase is 0.16 ohm. Calculate: a. Power supplied to the rotor (Air gap power) b. Rotor copper loss c. Shaft power d. Efficiency of the motor e. Shaft torque f What...
5 Marks) A 4-pole, 3 phase, 50 Hz, 230 V induction motor. Each phase of rotor winding b) has one-fourth the number of turns of each stator. The full-load speed is 1,455 rpm. The rotor resistance is 0.3 Ω and rotor standstill reactance is 1.0 Ω per phase. The rotor and stator windings are similar. Stator losses are equal to 50 Watts. Friction and windage losses are equal to 30 W. Calculate ) Blocked rotor voltage per phase. 2 Marks)...
5. A 208-V four-pole 60-Hz Y-connected wound-rotor induction motor is rated at 30 hp. Its equivalent circuit components are R=0.100 Ry=0.070. X - 10.00 R = 250 X; -0.2100 X=0.21002 Praw=500 W P =0.5% of input at full load For a slip of 0.05, find (a) The line current (b) The induced voltage in the rotor (c) The stator power factor (d) The rotor power factor (e) The rotor frequency (f) The stator copper losses (g) The core loss (h)...
A 480 V, 60 Hz, 4-pole-pair, three-phase, delta-connected induction motor has the following parameters: R1=0.42 Ω, R2=0.23 Ω, X1=0.48 Ω, X2=0.29 Ω, Xm=29.71 Ω where: R1 is the stator resistance R2 is the rotor resistance reflected in the stator; X1 is the stator leakage inductance; X2 is the rotor leakage inductance reflected in the stator; Xm is the magnetising inductance; The rotational losses are 2450 W. The motor drives a mechanical load at a speed of...
4. A certain four-pole 240-V-rms 50-Hz delta-connected three-phase induction motor operates at slip 5% at full load and has rotational losses (windage + friction) of 100 W. The stator resistance per phase is 0.2 Ohm. The results of no-load and locked-rotor tests on this motor are as follows: No-load test Locked-rotor test Line-to-line input voltage: 240 V 45 V Input active power: 1100 W 1300 W Input line current: 10 A 30 A Using the tests data, determine parameters of...