Molded case circuit breaker is also known as device circuit breaker, which is a contact, arc chamber, release and operating mechanism are installed in a plastic case of the circuit breaker 1. The shell adopts plastic insulator, which is used for isolating between conductors and grounding metal parts.
The molded case circuit breaker main component contact: is the circuit connection and the disconnection key spot. ARC extinguishing chamber: when the circuit is disconnected, it is used to extinguish the ARC and ensure the safety of the circuit. Release: divided into thermal magnetic release and electronic release. The molded case circuit breaker of the thermal magnetic release is a non-selective circuit breaker, which only has two protection modes, i. e. overload long-delay and short-circuit instantaneous The electronic over-current release has four protection functions: overload long delay, short-circuit short delay, short-circuit instantaneous and ground fault. Some new products also have Regioselectivity interlock function 1. According to the type of tripping curve, there are A-type tripping curve (tripping current is (2-3) In, suitable for protecting semiconductor electronic circuits, etc.) , B-type tripping curve (tripping current is (3-5) In, suitable for residential power distribution systems, etc.) , C-type tripping curve (tripping current is (5-10) In, suitable for protecting power distribution lines, etc.) , D-type tripping curve (tripping current is (10 -) In)2. Operating mechanism: Used for manual or electric operation of circuit breaker.
When the circuit is short-circuit or seriously overloaded, the armature of the overcurrent tripper will pull in, which makes the free tripping mechanism move and the main contact will disconnect the main circuit. The coil of the overcurrent release and the thermal element of the thermal release are connected in series with the main circuit to monitor the current condition in the circuit 1. When the circuit under-voltage, under-voltage release of the armature, but also make the free release mechanism action, the main contact disconnect the main circuit. The coil of the undervoltage release is connected with the power supply in parallel 1. When the tripping tripping button is pressed, the armature of the tripping tripping device absorbs and closes, so that the free tripping mechanism operates and the main contact disconnects the main circuit. In order to prevent the coil from burning out, a fretting switch is connected in series with the shunt release. When the shunt release is engaged through the armature, the microswitch changes from the closed state to the open state, and cuts off the control circuit.
The characteristics of the molded case circuit breaker are compact: all parts are sealed in the plastic case, auxiliary contacts, under-voltage release and shunt release are modular, the overall structure is very compact, basic can not repair 1. Operation Mode: more manual operation, large capacity can choose electric split 1. Protection function: according to the type of release, with different protection functions, such as overload, short circuit, under-voltage protection. Application: suitable for branch protection switch, widely used in distribution cabinet for shunt output and other scenarios, and the frame circuit breaker (commonly used in the total power supply protection switch) different.
Post time: Sep-26-2024