Welcome to Engineering Master. This article is about working of an electric rail engine. Please read my article Is the working of diesel and electric locomotive same? before reading this for proper understanding…
Electric rail engines are generally of two types, one is whose traction motor runs with AC and another is whose traction motor runs with DC.
Current reaches to circuit breaker from pantograph. These circuit breakers are used in case of emergency or short circuit to stop the current flow. The current collected by pantograph is single phase AC of 25000 Volts. This high amount of current is not required to run the engine. So the high voltage current is controlled by a Transformer.
AC Current from Transformer is changed to DC by using Rectifier.
If the traction motor is DC, then it takes power from here. And if the traction motor is AC, then the DC from rectifier is changed to 3 phase AC by using Inverter.