Question

) Explain how induction motors' speed can be controlled by frequency (for the below rated speed and above rated speed), include a sketch of the circuit configuration. The results of the no load and blocked rotor parameter tests on a 400 kW, 3300 V, three phase, 4 pole, 50 Hz, Y connected, squirrel cage induction motor is shown below:

i. Calculate the no load core loss? ii. Calculate the equivalent circuit parameters in Ohms including R₁, R2, X₁ and X2 Assume that X₁ = X₂. iii.Provide a diagram of a single-phase equivalent circuit for this induction motor(referring to stator side), labelling the components clearly and indicated the supply voltage correctly. Considering the same induction motor as Q( 4b) and presuming the motor is operating at rated voltage and frequency, with a slip of 2.8 % and stator current value of l₁ = 68.01<-15.93° A, calculate the following parameters: i. Motor's Power factor? ii. Input power? iii. Stator losses?

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