The speed cum energy monitoring system is suitable for conventional AC tap changer as well as for three phase locomotives. The speed cum energy monitoring system has four essential functional components, viz. (i) Pulse generator, (ii) Signal conditioning Unit, (iii) Master unit and (iv) Slave unit.The system consists of Pulse generator (Tachometer), Signal conditioning unit (SCU), Recorder and Indicator unit (Master) and only Indicator unit (Slave).