Design and Development of 250 A frame MCCB with Braking Capacity of 18 kA

Abstract

MCCBs are basically, Short Circuit Protective Device (SCPD). MCCB protects electrical load against short circuit and overload faults, which can damage electrical load and may lead to unsafe conditions at the site of installation. L&T offers d-sine range of MCCBs, which are available for nominal current ratings of 20 A to 1250 A. At present, L&T 250 A MCCB has Rated Ultimate Short Circuit Breaking Capacity (Icu) of 36 kA and Rated Service Short Circuit Breaking Capacity (Ics) of 18 kA. There is a requirement of cost effective 250 A MCCB for a particular segment of Low Voltage Switchgear market. This variant is required with Icu = 18 kA and Ics = 10 kA, with a target of product cost reduction by 10% of existing 250A MCCB. In this project, challenge is to develop the MCCB with open arc chute construction, instead of existing cassette construction and also to achieve cost reduction target. During the scope of the project, various stages of Product development such as Concept Development, Prototyping, Validation testing, Product design release and Product approval for manufacture will be worked upon.