1. Application Area
STB1 series moulded case circuit breaker is purpose lays in protection against overload, phase defect, short-circuit, etc. under 3-phase rotor cage induction motor system, it also can work as infrequent ON/OFF switch and isolator.
STB1 approves CCC, CE, TSE certificate.2. Working Circumstance
2.1 Altitude of the install place shall not be higher than 2000m.
2.2 Relative humidity shall not be higher than 50% when temperature at the highest +85ºC. Average humidity of the most humid month shall not exceed 90%, while average temperature of this month shall not be lower than -40ºC. 3. Working Theory & Structure Characteristics
STB1 circuit breaker is an integrated equipment which includes the functions of isolator, breaker, thermal relay, etc. it can effectively protect power system from malfunctions as overload, phase defect, temperature compensation, short-circuit, etc.
STB1 structure: connected to main circuit through thermal components, while motor suffers from overload, the bimetallic strip inside got heated up to trigger the circuit breaker to break off.
When motor suffers from phase defect, the bimetallic strip of this phase would cool down and recover its shape, by differential device's enlarging effect, circuit breaker would break off. While current reach the limit of instantaneous electromagnetic trip, magnetic core acts at once, forcing lever to cut off the current while driving operating module to trip, making circuit breaker to break off.
STB1 breaker is in consist of bottom foundation, contact support, arc-chute, insulating base, thermal-magnetic system(including instantaneous electromagnetic tripping unit, bimetallic strip, thermal components, etc.), differential device, current adjusting device, operating module, product cover, push button and so on.
STB1 breaker adopts flip-over direct-acting type double contacts structure, contact bridge, contact support & arc-chute are installed in the bottom foundation, thermal-magnetic system, static contact, operating module, differential device, current adjusting device are installed on base. There is a breaking test function, toggle the handle inside the "test" column according to the printed arrow to make sure the overload tripping function is reliable.