Explore the operating principles of three phase induction machine and demonstratecharacteristics of it using the equivalent circuit models and parameters such as efficiency,torque under different load conditions. Analyze the starting methods for single$-$phaseand three$-$phase induction machines. Critically evaluate their efficiency and makerecommendations for specific operational requirements for a $15$ kW$,400$V$,50$Hz$,4-$polethree$-$phase induction motor with a rated speed of $1440$ RPM$,$ calculate the startingcurrent, torque, and efficiency using DOL, star$-$delta, and VFD starting methods.Compare the results at $100\%$ load, assuming a power factor of $0\mathrm{.}85$ and total losses of$700$W$.$ Provide recommendations based on starting current, torque requirements, andenergy efficiency for optimal operational performance.