QUESTION 3 3.1 A single-phase 39 kW, 380 V, 50Hz induction motor operates on full load...
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.
An induction motor draws 1.0 kW at 0.8 lagging power factor from a 250 V, 60 Hz source. [38] (a) What value of capacitance must be placed in parallel with the motor to raise the line power factor to 93% lagging? (b) With the capacitor in service, what are the magnitudes of the motor current, capacitor current, and line current? Solution:
A 220 kW load having 0.8 lagging power factor is supplied from a 600 V (line to line) three-phase supply. A bank of power factor capacitors is delta connected Q2. (a) Draw neat schematic diagram showing the connection of the capacitor bank in Delta connection. (b) Determine the kVAR rating of each individual capacitor needed to bring power factor to 0.9 (c) Determine the capacitance of each capacitor in μF.
A 220 kW load having 0.8 lagging power factor is supplied from a 600 V (line to line) three-phase supply. A bank of power factor capacitors is delta connected. (a) Draw neat schematic diagram showing the connection of the capacitor bank in Delta connection. (b) Determine the KVAR rating of each individual capacitor needed to bring power factor to 0.9. (c) Determine the capacitance of each capacitor in uF.
QUESTION 6 (MULTI-PHASE SYSTEMS) A 400 v, 50 Hz, three-phase distribution system supplies a 20 kVA, three-phase induction motor load at a power factor of 0 8 lagging, and a star-connected set of impedances, each having a resistance of 10 Ω and an inductive reactance of 8 Ω Calculate the capacitance of delta-connected capacitors required to improve the overalil power factor to 0 95 lagging [14] TOTAL 1001 QUESTION 6 (MULTI-PHASE SYSTEMS) A 400 v, 50 Hz, three-phase distribution system...
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.
A 3-phase 50Hz 2-pole 440V (L-L rms) induction motor drive has a rated speed of 2955 rpm and rated torque of 35 Nm. This motor drives a load with a torque characteristic that increases linearly with speed such that it equals the load torque at the rated speed. It draws a current of 2.1 A(rms) per phase at the rated voltage at a power factor of 0.81 (lagging). The stator resistance Rs = 2.0 ohms. At the rated operating speed,...
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...
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...
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...