The main varieties of circuit breakers are: molded case circuit breakers, leakage circuit breakers, miniature circuit breakers, high breaking miniature circuit breakers, high breaking miniature earth leakage circuit breakers, and intelligent universal circuit breakers. The molded case circuit breaker will be discussed below.
Molded case circuit breakers can automatically cut off the current when the current exceeds the tripping setting. Plastic case refers to the use of plastic insulators as the outer casing of the device to isolate the conductors and the grounded metal parts. Molded case circuit breakers usually contain thermomagnetic trip units, while large models of molded case circuit breakers are equipped with solid state trip sensors. The trip unit is divided into: thermal magnetic trip and electronic trip. Commonly used rated currents are as follows: 15A, 25A, 30A, 40A, 50A, 60A, 75A, 80A, 100A, 125A, 160A, 200A, 225A, 250A, 315A, 350A, 400A, 500A, 630A, 800A, 1000A, 1250A, 1600A.
Molded case circuit breakers are used for making, breaking and carrying rated working current in the circuit, and can provide reliable circuit breaker protection when the load is overloaded, short-circuited, or under-voltage. The dynamic and static contacts and contact rods of the circuit breaker are designed to be parallel, and the dynamic and static contacts are disconnected by the electric repulsion generated by the short circuit, with high breaking capacity and strong current limiting characteristics.
There are NDM2, NDM3, NDM5 series of molded case circuit breakers, and the representation method of each manufacturer's model is different. The above is some sharing about Liangxin's plastic case circuit breaker models.