Could anyone tell me how to size the autotransformer size for starting of 6.0 kV,50Hz,1600 kW induction motor by autotransformer start method.The tap voltage required is 80%,65% and 50% of nominal line voltage.
I would first start with the speed torque curve of the motor and the load. With this calculate the allowable starting time to get the motor+load up to speed. Use the available taps on the auto-transformer to assist you on the starting time and torques available. Please be careful to compensate for the impedance of the transformer.
This should get you started.