Leakage-flux suppression in magnetic air breakers

THE MAGNETIC AIR CIRCUIT BREAKER, during the past two decades, has become a most effective and widely used circuit-interrupting device. The need for increased ratings in magnetic air circuit breakers has required critical studies of and improvements in the various factors involved in the interrupting process in these devices. One important factor, the magnetic field, has been improved in a number of ways, but the inherently large leakage flux has not been appreciably affected by these improvements. Studies made on such a-c energized magnetic field structures indicated that the total leakage flux was 50% or more of the total flux emerging from the magnet core.