A vcb circuit breaker is a kind of circuit breaker where the arc quenching takes place in a vacuum medium. The operation of switching on and closing of current carrying contacts and interrelated arc interruption takes place in a vacuum chamber in the vacuum type circuit breaker.
Good price vacuum circuit breaker for sale online, it is suitable for indoor use. Various vcb breakers with 11kv, 12kv, 15kv, 25kv, 33kv, 35kv, 40kv rated voltage are provided. Rate current of vcb circuit breaker is 630A, 1250A, 2000A, 2500A, 3150A. Acting to protect and control line is the function of vcb. Vacuum circuit breaker uses widely, it can be a flexible unit to protect line equipment with short-circuit situation or frequent operations.
Vacuum contactor is a device that can withstand multiple operations. It can cut off the load current at the same time, but can not break the short-circuit current. The vacuum contactor has two contacts, normally open and normally closed, and does not have the function of short-circuit current protection. When a given signal is received, it can perform separation and hold actions. It is recommended to use it together with the high-voltage vacuum circuit breaker in the high-voltage environment, which is more safe and reliable.
Vacuum circuit breaker is named because its arc extinguishing medium and the insulation medium of contact clearance after arc extinguishing are high vacuum.It is especially suitable for places requiring no oil, less maintenance and frequent operation. Circuit breakers can be configured in central cabinets, double cabinets and fixed cabinets for control and protection of high voltage electrical equipment. 11kV vacuum circuit breaker can play the role of overload protection, short circuit protection, control protection.
Vacuum circuit breaker structure is mainly divided into three parts: fixed contact, moving contact and arc shield placed in the arc breaking chamber.
The fixed and moving contacts of the 11kV vacuum circuit breaker are placed inside the arc shield. The vacuum interrupter is kept at around 10-6 Torr when it is closed. The moving contacts of the circuit breaker are move through a distance of 5 to 10 mm depending upon the operating voltage.
Metal bellows made of stainless steel are used to move the moving contacts. The design of the metal bellows is very important because the life of the indoor vacuum circuit breaker depends on the repeated operation capability of the element.
When the fault occurs in the system, the contacts of the indoor VCB circuit breaker are moved apart and hence the arc is developed between them. When the current carrying contacts are pulled apart, the temperature of their connecting parts is very high due to which ionization occurs. Due to the ionization, the contact space is filled with vapour of positive ions which is discharged from the contact material. The density of vapour depends on the current in the arcing. Due to the decreasing mode of the current wave, the rate at which they release vapor decreases, and after the current is zero, the medium regains its dielectric strength, provided that the vapor density around the point of contact decreases. Hence, the arc does not restrike again because the metal vapour is quickly removed from the contact zone.