7. A 3-phase, 300 kW, 2300 V, 60 Hz, 1800 r/min induction motor
is used to drive a compressor. The
motor has a full- load efficiency and power factor of 93 percent
and 87 percent, respectively. If the
terminal voltage rises to 2750 V while the motor operates at
full-load, determine the effect (increase or
decrease) upon
a. Mechanical power delivered by the motor
b. Motor torque
c. Rotational speed
d. Full-load current
e. Power factor and efficiency
f. Starting torque
g. Starling current
h. Breakdown torque
i. Motor temperature rise
j. Flux per pole
k. Exciting Current
l. Iron losses
7. A 3-phase, 300 kW, 2300 V, 60 Hz, 1800 r/min induction motor is used to...
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...
Question 11: (3 marks) A 6 pole, 60 Hz, star connected three-phase induction motor has a rating of Pm = 55 kW and line voltage = 420 V. The slip of the motor is 2% at 0.9 power factor lagging. If the full load efficiency is 95%, calculate the torque developed in the motor.
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 1500 kW, unity pf, 3-phase, Y-connected, 2300 V-(line), 30 pole, 60 Hz synchronous motor has a synchronous reactance of 1.95 22/phase. For this problem all losses may be neglected. a. Compute the max. torque in Nm which this motor can deliver if it is supplied with power from an infinite bus, and if its field excitation is constant at the value which would result in unity (1.0) pf at rated load. b. Now, suppose that the motor is supplied...
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 friction losses-51 kW following characteristics 4. iron losses in the stator-39 kW 5. locked rotor current at 6000 V-1800 A 6. active power to the stator with rotor locked 2207 kw Calculate under full-load voltage locked-rotor conditions a. Reactive power absorbed by the motor b. FR losses in the stator...
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....
3 phase, 37.3 Kw, 440 V, 50 Hz induction motor operates at full load with efficiency 89% and power factor 0.85 lagging. Calculate: A) The total KVA rating of capacitor required to rise full load power factor to 0.95 lagging. B) What is capacitance per phase if capacitor: 1) Delta connected. 2) Star connected.
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...
A three phase, 60 Hz induction motor rated at 440 V and 40 hp drives a load at 1710 rpm. The induction motor has the following impedances referred to the stator in /phase: R,=0.1512, X,=0.7512; R2=1.222,X=0.7522; X=25 12 . The core loss is 450 W and friction and windage loss is 250 W. Calculate the following 1. line current and power factor 2. Real and reactive input power 3. Air-gap power 4. Mechanical power and torque developed 5. shaft horse...