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Problem Statement

A centrifugal pump has a speed torque characteristic that may be described by the Torque-Speed relationship

TL= 1.40 x 10^-3 ωn^2 n-m

The maximum permissible speed is 1550 rpm. If a suitable 220V, 60 Hz 3-phase induction motor for the centrifugal pump has the following parameters referred to the stator side:

R1= 0.251Ω R2= 0.650Ω
X1=0.361 Ω X2= 0.361Ω
Xm=17.3Ω Rm=173Ω

Rotational losses of the motor are measured at approximately 400W. The motor is to be supplied from a 3-phase full-wave AC voltage controller in a first quadrant drive and the pump speed is to be varied from 1555 rpm down to 775 rpm.

Design and Analysis

Plot the torque speed characteristic of the pump.
Determine the maximum power required by the pump.
Determine the thyristor ratings of the AC voltage controller.
Select a motor (nearest standard) that can supply the load (Hint: determine the required horse power of the motor).
Starting with the equivalent circuit of the 3-phase induction motor, develop the power flow diagram.
Plot the torque speed characteristics of the motor.
Determine the range of the firing delay angle (angle of retard).
Plot the controller voltage against the firing delay angle
Plot the motor current against the firing delay angle
Plot the motor torque against the firing delay angle
Plot the motor PF against the firing delay angle
Plot the thyristor rms current against the firing delay angle
Plot the thyristor DC current against the firing delay angle

Requirements

Submit a detailed report that contains all the necessary simulation, modeling, analysis, and design computations along with graphs and selection charts. Attach as an appendix all supporting material used in the project.