General Rule 4 Breaking Principle 6 Installation mode 6 Application field 6 Standards and certificates 6 Operating safety 7 Accessories 8 Operating mechanism 8 Technical document 10 Quality system 10 Environmental management system 10 Health and Safety management system 10
The new VD4 vacuum circuit breaker is the perfect combination of ABB’s renowned R&D and manufacturing technology of arc extinguishing chamber and pouring pole, and advanced operating mechanism R&D, design and production technology.
The quench chamber of the VD4 medium pressure vacuum circuit breaker is poured integral in epoxy resin. The overall pouring pole structure is stronger, which can provide more adequate protection for the vacuum arc extinguishing chamber, and can eliminate the influence of dust and moisture on the external insulation capacity of the arc extinguishing chamber.
The arc extinguishing chamber permanently seals the main contact of the switch in a vacuum environment to form an arc breaking unit. Break the current in a vacuum
Vacuum circuit breakers do not require arcing and insulating media. In fact, there is no ionized material in the chamber. In any case, when the contacts are separated, the arc passage between the contacts consists solely of the metallic vapor of the contact material. The arc can only be maintained by external energy. When the main loop current disappears at natural zero crossing, the arc cannot be maintained. At this point, the rapidly decreasing current carrier density and the rapidly condensing vacuum metal vapor quickly restore insulation between the contacts. The vacuum chamber thus restores the insulation capacity and the ability to withstand the system’s transient recovery voltage, eventually extinguishing the arc.
Specially designed contact geometry and contact material, as well as very short arc burning time and very low arc voltage, so that the contact ablative degree is very low, ensure the arc extinguishing chamber long life. In addition, the vacuum protects the contacts from oxidation and contamination.
EL type operating mechanism
The contact of modern vacuum arc extinguishing chamber requires low separation speed, small stroke and light weight, and only requires the mechanism to provide little operating work. This ensures low wear on the operating system and means that the circuit breaker requires minimal maintenance. The VD4 circuit breaker uses a spring-loaded, free trip modular mechanical operating mechanism. The operation performance of circuit breaker has nothing to do with the specific operator. The operating mechanism is simple in concept and easy to use. It can be freely selected with secondary accessories that can be easily and quickly installed. The simple design idea brings high reliability of components.