Question 3 (20M) An AC motor has an internal resistance of R 4.0 S2. When powered...
A 120-V, series-wound motor has a field resistance of 4.0 and an armature resistance of 2.5 . (a) Determine the current drawn by the motor at the very instant it is switched on, i.e., when it has not started to rotate. (b) When it is operating at nominal speed, a back emf of 85.0 V is generated. How much current is drawn in this case? (c) What is the furnished mechanical power? (d) How much power is dissipated?...
b) A 1MW, 3300 V, 50 Hz, wye-connected, 3-ф, twenty four-pole, synchronous motor has a synchronous reactance of 3.24 2 per phase. Assume armature resistance is negligible. This machine is connected to an infinite bus-bars at 3300 V. Its field excitation is adjusted to provide P.F-1 at rated load Calculate: 0 the internal generated voltage EA and armature current la at rated conditions (S marks) ii) the maximum power and torqu e that the motor can deliver with its Ir...
3) The armature of a permanent-magnet dc motor has a resistance of 0.72 and draws a current of 50 A when the speed is 1500 r/min when the armature is connected to a source of 48 V, calculate the following: a) The induced emf, EA, and the torque, T, produced at this speed. b) The motor speed, n (in rpm), when the torque is 2 Nm. c) The armature current at 1600 r/min. d) The torque at 1600 r/min. e)...
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...
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...
A series AC circuit has a power source with frequency f = 60 Hz, peak voltage of epsilon_0 = 5.0 V, resistance R = 0.50 omega, capacitance C = 320 mu F, and inductance L = 0.40 H. what is the period circuit? What is the maximum current through the inductor? What is the largest power reached in resistor? Suppose the power supply reaches maximum voltage at time t_1, how the long after t_1 does the current though the resistor...
A 220 V DC shunt motor has an armature resistance, Re-0.1 S2, a field resistance, Ry=100 12, and negligible rotational losses. Under certain load conditions, the shunt motor runs at 1600 rpm while drawing a total current, I = 100 A. Determine: a. the output power of the motor; b. the output torque in N-m; and, c. the efficiency Without making any changes to the applied voltage or the field, the motor operates with a new M mechanical load that...
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...
3. A controlled single-phase fiull-wave controlled rectifier is connected in a de motor drive in Figure 4. The de motor armature inductance can be assumed large enough such that any motor curent ripple is negligible. (a) Assuming negligible supply reactance, show that the average rectifier output voltage V, in tems of the supply ms voltage E and the firing angle a, is given by 2/2E (6 marks) cos a _ (b) Given that the supply voltage is 230V, 50HZ and...
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...