Circuit breaker is a kind of switch device which can control the mechanical current (carrying and breaking the current under the condition of abnormal circuit) under specified conditions. The main components of circuit breaker can be divided into molded case circuit breaker, miniature circuit breaker and frame circuit breaker. What are the construction and installation requirements and working principles of miniature circuit breaker?

微型断路器施工安装要求和工作原理介绍

Construction and installation requirements and working principle of miniature circuit breaker

微型断路器施工安装要求：

Construction and installation requirements of miniature circuit breaker:

1)断路器的安装应符合GB13955-92标准及产品说明书的要求。

1) The installation of circuit breaker shall meet the requirements of GB 13955-92 standard and product manual.

2)断路器的安装应充分考虑供电线路、供电方式、供电电压及系统接地型式。

2) The installation of circuit breaker shall fully consider the power supply line, power supply mode, power supply voltage and system grounding type.

3)断路器的额定电压、额定电流、短路分断能力、分断时间应满足被保护供电线路和电气设备的要求。

3) The rated voltage, rated current, short-circuit breaking capacity and breaking time of the circuit breaker shall meet the requirements of the protected power supply line and electrical equipment.

4)断路器的安装接线应正确，在不同的系统接地形式的单相、三相三线、三相四线供电系统中剩余电流保护器的接线不同，应给以充分注意。

4) The installation and wiring of the circuit breaker should be correct. In the single-phase, three-phase three wire, three-phase four wire power supply systems with different system grounding forms, the wiring of the residual current protector is different, which should be given full attention.

微型断路器工作原理：

Working principle of miniature circuit breaker:

微型断路器由操作机构、触点、保护装置(各种脱扣器)、灭弧系统等组成。其主触点是靠手动操作或电动合闸的。主触点闭合后，自 由脱扣机构将主触点锁在合闸位置上。过电流脱扣器的线圈和热脱扣器的热元件与主电路串联，欠电压脱扣器的线圈和电源并联。当电路发生短路或严重过载时，过电流脱扣器的衔铁吸合，使自 由脱扣机构动作，主触点断开主电路。当电路过载时，热脱扣器的热元件发热使双金属片上弯曲，推动自 由脱扣机构动作。当电路欠电压时，欠电压脱扣器的衔铁释放。也使自 由脱扣机构动作。

The miniature circuit breaker is composed of operating mechanism, contact, protection device (various releases), arc extinguishing system, etc. The main contact is manually operated or electrically closed. After the main contact is closed, the free tripping mechanism locks the main contact in the closing position. The coil of the over-current release and the thermal element of the thermal release are connected in series with the main circuit, and the coil of the under voltage release is connected in parallel with the power supply. When the circuit is short-circuit or seriously overloaded, the armature of the over-current release will pull in to make the free release mechanism act, and the main contact will disconnect the main circuit. When the circuit is overloaded, the thermal element of the thermal release will generate heat and bend the bimetallic sheet to push the free release mechanism. When the circuit is under voltage, the armature of the under voltage release is released. It also makes the free release mechanism act.