Static overcurrent tripping device for low-voltage breakers

In an effort to overcome some of the outstanding shortcomings of presently used electromechanical tripping devices, a static type using semiconductors has been developed. Advantages include greater accuracy, simplified field testing, greater flexibility, and reduced maintenance Low-voltage air circuit breakers rated at 600 volts and less are used as protective and switching devices on plant distribution systems. They may be installed in metal-clad switchgear, on switchboards, or they may be separately mounted. Designed to interrupt currents of 15 to 100 kiloamperes at 600 volts (and higher at lower voltages), these breakers are necessary for complete system protection where the greatest degree of service continuity is desired.