Question

Draw a neat labelled block diagram of AC electric locomotive. State the function of each part.

Answer 1

labelled diagram ofAC electric locomotive: 

Function of AC electric locomotive Parts: 1) Overhead contact wire: Supply of 1-ph, 25KV, 50Hz, AC is given to overhead conductor. 2) Current collecting device: It collects current from overhead contact wire and passes it to tap changing transformer through circuit breaker. 3) Circuit breaker (C.B): It is connected in between current collecting devices and tap changing transformer. SF6 circuit breaker is used. To disconnect locomotive equipments whenever there is fault. It opens automatically when train passes neutral zone (from zone No.1 to Zone No.2) 4) On load tap changing transformer: It changes the tap without disconnecting the load on transformer. Its purpose is to vary the voltage for speed control of traction motor. 5) Traction Transformer: It step down input voltage 25 KV to working voltage of traction motor (1500V/3000V). 6) Rectifier: It converts secondary voltage of transformer into DC supply. 7) Filter circuit (smoothing reactor): It is used to obtain pure DC supply. 8) Motor control unit: It controls operation of traction motor. 9) Traction Motor: It gives mechanical power to run the train i.e. DC series motor which is used as traction motor.