Abstract:

Molded case circuit breakers (MCCB) below 125 A are main force in the field of MCCBs.The main way to integrate and improve them is to elevate 63 A and 100 A products to 125 A with short circuit breaking being the main difficulty.It is possible to preliminarily increase its breaking capacity through gas producing materials.Quantified data analysis can be conducted on the condition of the arc extinguishing chamber’s grid segments through the measurement and analysis of grid voltage.The simulation of electromagnetic force is used to optimize the magnetic field of the contact part.By improving the design, the new 125A product can replace the original product and meet the performance requirements while reducing the cost of the main product.

Key words: moulded case circuit breaker (MCCB), short circuit breaking capacity, grid voltage measurement, finite element simulation (FEM), electromagnetic force analysis