Development of Overload Protection Trip Unit for Higher Rating Current of MCCB

Dilavarsinh Dodia, Bimal Mawandiya, Nidhi Bhatewara
Journal of Basic and Applied Engineering Research   unpublished
This paper deals a new development of overload protection trip unit of electromechanical release for higher rating current of moulded case circuit breaker (MCCB). This is a replacement of microprocessor release by using both mechanical as well as electrical concept. Electromechanical release provides two types of protection which are overload current protection and the short-circuit protection. The thermal property of bimetal (gets elongated when heating) is used to sense the overload of
more » ... overload of current and magnetic property (magnetic flux/induction) is used to sense the short circuit. This paper deals with the protection against overload of the current. Here by using reverse engineering concept, bimetal for higher rating current is selected and the shape and size of the bimetallic strip is decided as per the movement required for trip plate to trip the MCCB. The prototype of new developed bimetal has also been validated on MCCB. After completion of concept validation, the proposed bimetallic strip of electromechanical release would be consider for higher rating current MCCB.