2. When the terminal voltage of this motor is 1 pu, compute the starting current RMS and the full...
24. Synchronous motor delivers reactive power when: a. The terminal voltage leads the induced voltage in armature windings b. The terminal voltage lags the induced voltage in armature windings c. Synchronous motor is an inductive load; it absorbs reactive power. Capacitors deliver reactive power d. The terminal voltage is less than the induced voltage in armature windings e. None of the above. 25. In a synchronous machine, if magnetic field of the rotor lags the stator field by a mechanical...
Problem 3 (40 points) An induction motor is to be started at a reduced voltage. If the motor starts at full-voltage the starting current will be four times the full-load current. The full-load slip is 3%. The starting torque is to be no less than 25% of the full-load torque Determine the factor by which the motor terminal voltage has to be reduced at the time of the motor starting
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)...
A three-phase load has a voltage of 1.0 pu with current 0.1 pu. The current lags the voltage by 30 degrees. A lossless capacitor is to be installed in parallel with the load to improve the overall power factor to 0.95 lagging. Find the amount of reactive power that needs to be injected by the capacitor. Select one: a. 0.0646 pu b. 0.0215 pu C. 0.0785 pu d. -0.0215 pu
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) One phase equivalent parameter of a three-phase, 460V, 1740d / d, 60Hz, 4-pole, rotor wound asynchronous motor values are given below. R1 = 0.25Ω, R’2 = 0.2Ω, X1 = X’2 = 0.5Ω, Xm = 30Ω Rotary losses are 1700W. While the rotor terminal ends are short-circuited, find the following requirements. a) (i) Find the starting current when the motor is supplied with nominal voltage? (ii) Find the starting torque? b) (i) Find the slip at full load? (ii) Find...
3, A 34, 400-V 50-Hz induction motor takes 4 times the full-load current and develops twice the full- load torque when direct-switched to 400-V supply. Calculate in terms of full-load values (a) the line curent, the motor current and starting torque when started by an auto-starter with 50% tap and (b) the voltage that has to be applied and the motor current, if it is desired to obtain full-load torque on (a) 100%, 200%, 50% (b) 228 V, 282%) starting...
Please answer questions 4-6 not number 1. Number 1 is for the
values in the circuit only
1. A three-phae, 4-pole, 75 kW, 460-V induction motor has the following single-phase equivalent circuit parameters in ohms-per-phase: R 24.5 x 103, R2 55.2 x 103, X 0.267, X2 0.277, X 19.8 4. This motor is now connected to a power grid through a transmission line. The grid and transmission line are represented by a Thevenin equivalent voltage source at 1 pu with...
3. (30) A simple power system, shown below, is made up of a synchronous generatcr connected to a synchronous motor through a couple of transformers and a transmission line. The reactances of the different elements of the system are all given in pu as: Xsg-0.5 X of each transformer-10 % Xsm-0.5 X transmission line 0.3 The synchronous motor is connected to an infinite bus Hint: The great advantage of an infinite bus is that it always remains constant and our...
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...