Design of an Automatic Water Level Controller Using Mercury Float Switch

Abstract

This paper presents the design of an automatic water level controller aimed at providing an appropriate control to pump water to an overhead thank when empty and automatically stop the pump when the tank is full. The system incorporates two mains contactor which are energized to provide a direct online start of the motor. An over load relay which senses the presence of excess current and disconnect the supply and a mercury flood switch which uses the Archimedes principle of floatation to provide the electrical contact to switch ON or OFF supply to the motor when the tank is empty or full respectively. This is capable of providing a seamless utilization of water at domestic and industrial level without causing spillage.