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Which type rotor of three-phase squirrel-cage motor has low starting torque, high starting current and good...
The starting torque of a three-phase synchronous motor is increased when SE O ou h atic...
The starting torque of a three-phase synchronous motor is increased when SE O ou h atic tio co e rotor electromagnet is turned on. a. b. the rotor electromagnet is turned off. c, the power factor of the ac power network is unity. d. dc power is applied to one of the stator windings. 2. When a synchronous motor without load is connected to a three-phase ac power network, the resulting power factor depends on a. the speed of the...
A three phase induction motor draws a starting current which is five times the full load...
A three phase induction motor draws a starting current which is five times the full load current with direct on line starting, while developing twice the full load torque. Q2.1. Based on the two facts that starting current is proportional to the applied voltage and that the starting torque is proportional to the square of the applied voltage, determine voltage (as a per cent of rated voltage) required to obtain a starting torque equalling the full load torque. (10 marks)...
6. A 3-phase 2.2 kV 25 Hz squirrel cage induction motor draws a line current of...
6. A 3-phase 2.2 kV 25 Hz squirrel cage induction motor draws a line current of 224 A and a total power of 777 kW when operating at full load. The full-load speed is 245 rpm. The stator is wye connected and has an effective resistance per phase of 0.125 Ω. The stator iron (core) loss is 8.88 kW; friction and windage losses are 4.54 kW. Calculate at full-load conditions: b. power supplied to the rotor, a. the power factor;...
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2) (a) Describe the principle of operation of 3-phase induction motor. [8 Marks](b) Explain slip as applied to three phase induction motor. [2 Marks]3) Derive an expression for the total armature torque of DC motor. [10 Marks]5) List the starting methods used in starting 3-phase induction motors and explain any two of these methods. [10 Marks]6) (a) A 60 kW, 400 V d.c. shunt motor has 4 poles a 2-circuit wave-connected armature winding with 450 conductors. The flux per pole...
1. A 15 hp, 4 pole, 208 V, 60 Hz, Y-connected, three-phase squirrel cage induction motor has the ...
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...
1. A 300 V compound motor has armature resistance 0.18 Ω, series field resistance 0.3 Ω...
1. A 300 V compound motor has armature resistance 0.18 Ω, series field resistance 0.3 Ω and shunt field resistance 100 Ω. The rotational losses are 200 W. On full load the line current is 25 A and the motor runs at 1800 rpm. Determine: (i) the developed mechanical power (ii) the output power (iii) the output torque (iv) the efficiency at full load 2. A 120 V series motor has 0.2 Ω field resistance. On full load, the line...
A two-pole, 75kW, 440 V, 50 Hz, Y-connected, three-phase squirrel cage induction motor has the fo...
Please solve this question. Thank you.
A two-pole, 75kW, 440 V, 50 Hz, Y-connected, three-phase squirrel cage induction motor has the following parameters, in Ω/phase referred to the stator: R1-0.075, XI 0.17, xm-72, R2-0.065 and X-0.17. Its rated slip is 4%. Assume that the mechanical losses are 1 kW and the core losses are 1.1 kW. Compute: a. The rated input current b. The rated power factor. c. The pullout torque d. The induced and load torques at rated conditions....
14. The following details are known about a 200 hp, 500 V, 435 rpm de shunt motor: full-load current is 330 A, insulation class is H, weight is 3400 kg, external diameter of the frame is 915 mm a...
14. The following details are known about a 200 hp, 500 V, 435 rpm de shunt motor: full-load current is 330 A, insulation class is H, weight is 3400 kg, external diameter of the frame is 915 mm and length of the frame is 1260 mm. If the motor is running at full-load, calculate: a. the total losses and efficiency. b, the approximate shunt field exciting current if the shunt field causes 15% of the total losses. the value of...
Example 20-4. A 200 hp (150 kW), 460 V, 3-phase, 3520 r/min, 60 Hz induction motor has a locked-rotor torque of 600 Nom and a locked-rotor current of 1400 A (same motor as in Example 20- 2). Two auto...
Example 20-4. A 200 hp (150 kW), 460 V, 3-phase, 3520 r/min, 60 Hz induction motor has a locked-rotor torque of 600 Nom and a locked-rotor current of 1400 A (same motor as in Example 20- 2). Two autotransformers, connected in open delta, and having a 65 percent tap, are employed to provide reduced-voltage starting. Calculate a. The apparent power absorbed by the motor b. The apparent power supplied by the 460 V line c. The current supplied by the...
(might be 1 or 2, MCQ questions were having images given with them, which we couldn't...
(might be 1 or 2, MCQ questions were having images given with them, which we couldn't insert, so ignore those questions if you cannot answer, sorry for inconveinience created, i tried to delete them but might be couldn't done all) 3) Single phase induction motors work because: a) The oscillating magnetic field can induce starting torque in a rotor. b) The oscillating magnetic field can induce running torque in a rotor. c) A capacitance or inductance can create the phase...
The starting torque of a three-phase synchronous motor is increased when SE O ou h atic tio co e rotor electromagnet is turned on. a. b. the rotor electromagnet is turned off. c, the power factor of the ac power network is unity. d. dc power is applied to one of the stator windings. 2. When a synchronous motor without load is connected to a three-phase ac power network, the resulting power factor depends on a. the speed of the...
6. A 3-phase 2.2 kV 25 Hz squirrel cage induction motor draws a line current of 224 A and a total power of 777 kW when operating at full load. The full-load speed is 245 rpm. The stator is wye connected and has an effective resistance per phase of 0.125 Ω. The stator iron (core) loss is 8.88 kW; friction and windage losses are 4.54 kW. Calculate at full-load conditions: b. power supplied to the rotor, a. the power factor;...
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...
Please solve this question. Thank you.
A two-pole, 75kW, 440 V, 50 Hz, Y-connected, three-phase squirrel cage induction motor has the following parameters, in Ω/phase referred to the stator: R1-0.075, XI 0.17, xm-72, R2-0.065 and X-0.17. Its rated slip is 4%. Assume that the mechanical losses are 1 kW and the core losses are 1.1 kW. Compute: a. The rated input current b. The rated power factor. c. The pullout torque d. The induced and load torques at rated conditions....
14. The following details are known about a 200 hp, 500 V, 435 rpm de shunt motor: full-load current is 330 A, insulation class is H, weight is 3400 kg, external diameter of the frame is 915 mm and length of the frame is 1260 mm. If the motor is running at full-load, calculate: a. the total losses and efficiency. b, the approximate shunt field exciting current if the shunt field causes 15% of the total losses. the value of...
Example 20-4. A 200 hp (150 kW), 460 V, 3-phase, 3520 r/min, 60 Hz induction motor has a locked-rotor torque of 600 Nom and a locked-rotor current of 1400 A (same motor as in Example 20- 2). Two autotransformers, connected in open delta, and having a 65 percent tap, are employed to provide reduced-voltage starting. Calculate a. The apparent power absorbed by the motor b. The apparent power supplied by the 460 V line c. The current supplied by the...
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