Design of AC Machines — Summer 2022

State the rules for the selection of rotor slots in 3-phase induction motor.

State the effect of air gap length on the performance of a 3-phase induction motor. Explain any one in brief.

Derive an output equation for 3-ф induction motor with usual notation.

Explain dispersion co-efficient applied to induction motors. 0

How design of 1-phase and 3-phase induction motor differ from each 0 other

Prove that torque produce by 5TH harmonics is in backward direction & 0 7TH harmonics is in forward direction.

Explain the deciding factor for stator slots of a 3-phase induction motor

Why auxiliary winding needed in 1-phase induction motor.

Write output equation in 1-phase induction motor. Give identification of each notation in it.

Explain the design procedure of rotor for 1-ф induction motor with usual notation.

Important of circle dia. in design of motor.

Define and explain the term “short circuit ratio” of a synchronous generator.

Explain the design procedure of an auxiliary winding in case of resistance split phase 1-ф induction motor with usual notation.

State different materials used in alternator construction.

Explain purpose damper winding in alternator

Find the main dimensions, number of turns per phase & number of stator slots of 3-ɸ, 13750V,50Hz, 1500 RPM, star connected alternator from given data : . Bav= 0.62 Wb/m2, ac=40000 Amp-cond/m, Kw=0.95, peripheral velocity= 79m/s., Rating=12MVA.

Explain different types of rotor used in 3-phase induction motor construction.

Explain different excitation system in alternator

Calculate the diameter, core length, no of conductors of the stator , size of conductor, no of stator slots of 75 MVA, 96 pole,50 HZ,low speed star connected hydro generator having voltage per phase is 8000V. Assume Bav= 0.64 Wb/m2, ac=40625 Amp-cond/m, Kw=0.955, peripheral velocity= 39.5m/s1

Explain different types of rotor used in alternator construction.

Explain why a turbo alternator has smaller diameter and large length but hydro alternator has larger diameter and small length?

Find the main dimensions, number of stator turns per phase & number of stator slots for a 25KW, 415V, 50Hz, 2880rpm,3-ф delta connected induction motor. Assume that: specific magnetic loading=0.48wb/m2, specific electric loading=21000ac/m, Efficiency=88%, power factor=0.87, stator winding factor=0.9451. Take ratio (L/τ)=0.7

Explain the advantages of finite element method

Discuss the design differences of a salient pole and non salient pole synchronous machines

Explain significance of FEM in design problem