主断路器兼有控制和保护两种用途，比一般断路器有较高的机械寿命。主断路器

Main circuit breaker both control and protection for both purposes, have a higher than normal mechanical life of the circuit breaker. The main circuit breaker is a main traction transformer breaking load currents (including no-load excitation current), a strong air flow can thus quickly cutting a small inductor current, caused by the closure of a large over-voltage. In order to suppress the overvoltage, the interrupter contacts parallel movement between a set of nonlinear resistor. Amount of compressed air used directly as the arc medium, it has to be filtered, is fed to the main circuit breaker after drying. In order to adapt to the complex environmental conditions, the main circuit breaker is a vacuum circuit breaker is gradually improved with a sealing member, both to improve the reliability and reducing maintenance.

The main circuit breaker has both control and protection purposes, and has a higher mechanical life than the general circuit breaker. The main work of the main circuit breaker is to break off the small load current of the traction transformer (including the empty excitation current), and the strong air flow can quickly cut off such a small inductive current, which causes a large overvoltage caused by intercepting the flow. In order to suppress the overvoltage, a set of nonlinear resistors is paralleled between the static contacts in the arc-out chamber. The amount of compressed air is used directly as an arc-killing medium, so it must be filtered and dried before it can be fed into the main circuit breaker. In order to adapt to complex environmental conditions, the main circuit breaker is gradually being improved to a vacuum circuit breaker with sealing elements, which can improve reliability while reducing maintenance work.

The main circuit breaker has both control and protection purposes, and has a higher mechanical life than the general circuit breaker. The main work of the main circuit breaker is to break the small load current (including the no-load excitation current) of the traction transformer. Strong air flow can quickly cut off such small inductance current, resulting in large over-voltage due to the closure. In order to suppress the over-voltage, a set of nonlinear resistors are connected in parallel between the dynamic and static contacts of the arc extinguishing chamber. Compressed air is directly used as arc extinguishing medium, so it must be filtered and dried before being sent to the main circuit breaker. In order to adapt to the complex environmental conditions, the main circuit breaker is gradually improved to a vacuum circuit breaker with sealing elements, which can not only improve the reliability, but also reduce the maintenance workload.<br>