ABB VD4 24.20.25 P275 IEC indoor vacuum circuit breaker1VCF337114R0543

VD4 medium voltage circuit breakers use vacuum interrupters embedded in the poles. This construction method makes the poles particularly sturdy and protects the interrupter from shocks, dust and condensation. VD4 circuit breakers are the best choice for the majority of modern electricity distribution applications and are used in transformer and distribution substations to control and protect motors, transformers, capacitor banks and for protecting cables.

The VD4 medium voltage circuit-breakers use vacuum interrupters embedded in resin poles. Embedding the interrupter in resin makes the circuit-breaker poles particularly sturdy and protects the interrupter against shocks, accumulation of dust and humidity. The vacuum interrupter houses the contacts and makes up the interrupting chamber.

ABB VD4 Circuit Breaker VD4 1225-40 Serial-No. 1VBV0 7047058 /4012/07 IEC 62271-100 2007 Since high dielectric strength can be reached in the vacuum, even with minimum distances, circuit breaking is also guaranteed when the contacts separate a few milliseconds before natural current zero crossing. The special shape of the contacts, the material used, as well as the limited duration and low voltage of the arc, guarantee minimum contact wear and long life. In addition, the vacuum also prevents contact oxidation and contamination. Operating mechanism The low speed of the contacts, their reduced travel and exposed conductive part, limit the energy required for the operation and therefore guarantee extremely low wear on the system. This means that the circuit breaker only requires very little maintenance. VD4 circuit breakers have mechanical operating mechanisms with stored energy and free trip. These characteristics allow opening and closing operations to be performed independently of the operator. The operating mechanism is of a simple design, easy to use and can be customized with a wide range of accessories which are straightforward and rapidly installed. This simplicity enhances the reliability of the apparatus. The structure The operating mechanism and the poles are fixed to a metal frame which also acts as the support for the fixed version of the circuit breaker. The compact structure is sturdy and ensures mechanical reliability. Apart from the isolating contacts and the cord with plug for connecting the auxiliary circuits, the withdrawable version is complete with truck for racking it in and out of the switchgear or enclosure with the door closed. Rated Voltage: 12kV Rated Frequency: 50/60 Hz Rated Power-Frequency Withstand Voltage: 28kV Rated Lightning Impulse Withstand Voltage: 75kV Rated Normal Current: 1250A Rated Short-Circuit Breaking Current: 40kA Rated Short-Time Withstand Current: 40kA Duration Of Short-Circuit: 3s Short-Circuit Making Current: 100kA Rated Operation Sequence: O-0.3s-CO-15s-CO

These new VD4 circuit breakers exemplify ABB’s proven vacuum interrupter engineering and manufacturing technology, as well as the superior design standards employed in the production of circuit breakers. VD4 medium voltage circuit breakers use vacuum interrupters embedded in the poles. This construction technique makes the poles of the circuit breaker particularly sturdy and protects the interrupter from shocks, dust and condensation. The vacuum interrupter houses the contacts and forms the interruption chamber. 1 Upper terminal 2 Vacuum interrupter 3 Enclosure/pole 4 Stem of moving contact 5 Lower terminal 6 Flexible connection 7 Tie-rod spring fork 8 Tie-rod 9 Pole fixing 10 Connection to operating mechanism Vacuum interrupter embedded in the pole Vacuum current interruption The vacuum circuit breaker does not require an interrupting and insulating medium. Interrupters do not, in fact, contain ionizable material. The electric arc that generates when the contacts separate is merely formed by melted and vaporized contact material. Supported by the external energy, the electric arc persists until the current annuls near natural zero crossing. In that instant, the dielectric properties are very rapidly restored by the sharp reduction in the density of the conveyed load and rapid condensation of the metallic vapor. Thus the vacuum interrupter recovers insulating capacity and the ability to withstand transient recovery voltage, thereby definitively extinguishing the arc. Vacuum interruption technique • Vacuum contacts protected against oxidation and contamination • Vacuum interrupter embedded in the pole • Interrupter protected against shocks, dust and condensation • Operation under different climatic conditions • Limited switching energy • Stored energy operating mechanism with anti- pumping device supplied as standard • Simple customizing with a complete range of accessories • Fixed and withdrawable version • Compact dimensions • Sealed-for-life poles • Sturdy and reliable • Limited maintenance • Circuit breaker racked in and out with door closed • Incorrect and hazardous operations are prevented thanks to special locks in the operating mechanism and truck • High environmental compatibility Versions available VD4 circuit breakers are available in the fixed and withdrawable versions with front operating mechanism. The withdrawable version is available for UniGear ZS1, ZS2, ZS8.4 and UniSec switchgear and for PowerCube and Powerbloc enclosures. Fields of application VD4 circuit breakers are used in power distribution systems for controlling and protecting cables, transformer and distribution substations, motors, transformers and capacitor banks. Standards VD4 circuit breakers comply with IEC 62271-100 Standards and those of the major industrialized countries. VD4 circuit breakers undergo the tests indicated below and guarantee the safety and reliability of apparatus in service in every installation. • Type tests: temperature rise, tests to verify the insulation level (tests with rated lightning impulse withstand voltage and power frequency withstand voltage), peak and short-time withstand current tests, mechanical life, shortcircuit current making and breaking capacity. • Individual tests: insulation of the main circuits with voltage at power frequency, auxiliary and operating circuit insulation, measurement of the main circuit resistance, mechanical and electrical