B4. (a) A 380V, 50 Hz, 4-pole, 1460 rev/min, star-connected three-phase induction motor is driven by a Variable Voltage

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B4 A A 380v 50 Hz 4 Pole 1460 Rev Min Star Connected Three Phase Induction Motor Is Driven By A Variable Voltage 1 (36.81 KiB) Viewed 23 times

B4. (a) A 380V, 50 Hz, 4-pole, 1460 rev/min, star-connected three-phase induction motor is driven by a Variable Voltage Variable Frequency (WVVF) controller. The motor has the following per phase circuit parameters referred to the stator at rated load, • R : Stator Resistance =0.5 12 • R',: Referred Rotor Resistance =0.392 • X, : Stator Reactance = 1.52 • Xy:Referred Rotor Reactance = 1.52 • Xm: Magnetizing Reactance = 30 • Re: Core Loss Resistance = 12 (3 marks) (3 marks) (i) Evaluate the motor slip at rated speed, (ii) Draw the per phase equivalent circuit of the motor, (ii) Evaluate the stator current at rated load, and (iv) Evaluate the motor torque at rated load. (4 marks) (4 marks) (b) Give three reasons on why variable voltage variable frequency (6 marks) controller is commonly employed in industrial application.