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-23 An 8-pole, 230-V, 60-Hz, A-connected, three-phase induction motor has a rotor impedance of 0.025 +...
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...
Two tests were performed on a 230-V, 60-Hz, 4-pole, Y-connected, three-phase induction motor and the obtained data are given in the table below. The friction and windage loss is 15 W, and the stator winding resistance between any two lines is 3.96ohm Determine: 1) The equivalent circuit parameters of the motor 3) The motor efficiency at a slip of 8%. No-load test 137 0.43 230 Blocked-rotor test 70 1.18 47 3-phase power input, W Line-line voltage, V
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...
Q3. A single-phase, 120 V, 60 Hz, four-pole, split-phase induction motor has the following equivalent circuit parameters: Stator parameters: The Main winding (R =1.512, X=2.522), and the auxiliary winding (R=2.512, X=2.52), Rotor parameters referred to the stator side: (R=1N, X=1.592). The magnetizing reactance is equal to 4082. (a)Determine the standstill impedances of both windings. (b)Determine the starting torque and the starting current of the motor if it is started from rated voltage mains as a split phase induction motor. (c)Determine...
d) A 440V, 50 Hz, 4-pole, 3 phase induction motor has a total leakage impedance of (0.3 +j5.5+0.25/s) ohm (delta phase). Determine the external resistance to be inserted in each phase of the rotor winding such that the motor produce a gross torque of 130 N-m at a speed of 1300 rpm. (10 Marks)
d) A 440V, 50 Hz, 4-pole, 3 phase induction motor has a total leakage impedance of (0.3 +j5.5+0.25/s) ohm (delta phase). Determine the external resistance to...
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
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 230 V, 50 Hz, three-phase, Y-connected, 6-pole induction motor has the following per-phase parameters R-0.07 Ro 00 0.08 Ω x, x, 0.3 xm 6.33 At a slip of 2%, determine the followings using approximate equivalent circuit of the motor i) The motor speed in rev/min and rad/s. ii) The rotor current. ii) The stator current. iv) The induced torque. v) The efficiency of the motor.
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
a four pole 60-Hz, 440-V three phase induction motor is supplied by a variable voltage variable frequency source. the motor has negible stator resistance and a rotor resistance of 0.1 ohm. the total inductance is 2 x 10 ^-3 H. a)find lowest possible frequency and voltage of proper operation. b) determine the starting torque, the speed at maximum torque, and the router's applied voltage when supply frequency is 8 hz, 40 hz and 60 hz