Vacuum Circuit Breaker

Sectional view of a Vacuum Circuit Breaker, marketed by M/s Driescher Picnicker Madras is shown is Fig. (6) the most important part is the vacuum interrupter, blown up view of which is given in Fig. (7) When the contacts separate, the current to be interrupted initiates a metal vapor arc discharge and flows through this plasma until the next current zero.

 

The arc is then extinguished and the conductive metal vapor condenses on the metal surfaces within a matter of microseconds.

As a result, the dielectric strength in the break builds up very rapidly.

The self generated field causes the arc root to travel, thereby preventing local overheating when large currents are being interrupted. Certain minimum current is necessary to maintain the metal vapor arc discharge.

 

Current of a lesser value is chopped prior to current zero, causing unduly high voltages, as may happen during interruption of no load magnetizing currents of unloaded Transformers.

The rapid build up of the dielectric strength in the break enables the arc to be safely extinguished even if contact separation occurs immediately prior to current zero the maximum arcing time for the last pole to clear is stated to be 15 ms.

 

Further the arc voltage developed in vacuum interrupter is low (say between 20 to 200 V) due to high conductivity of metal vapor plasma.

 

For there reasons the arc energy developed in the break is very small. High Switching life is claimed on this account. Performance is claimed to be immune to pollution because of interrupters being hermetically sealed.

The manufacturing range of M/s Driescher Panicker covers Vacuum Circuit Breakers up to rated voltage of 36 kV.

Vacuum Circuit Breakers are specially suited in industrial applications, where the Switching frequency is high combined with high degree of pollution. www.sayedsaad.com

Vacuum Circuit Breaker
Fig (6)

1 - Vacuum Interrupter
2 - Terminal

3 - Flexible connection .
4 - Support insulators.

5 - Operating rod.
6 - Tie bar.
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7 - Common operating shifts .
8 - operating corn .

9 - Locking cam.
10 - Making spring .

11 - Breaking spring.
12 - Loading spring.

13 - Main link.


Fig (7)

Vacuum Circuit Breaker

1-  cast resin post insulator

2-  upper connection

3-  upper contact support

4- 5- fastening nuts

6- Rear pull strap

7- Front pull strap

8- vacuum Switching chamber

9- contact Switch with toroidal

    contact  Lower contact support

    Consisting of :-

10.1 transmission lever

10.2 burn-off indicator

10.3 actuation crank

10.4 actuation lever

10.5 telescope rod with contact spring

11    hook stick

Fig (8)

Construction of the Switch pole type VA, VXC

 

Vacuum Circuit Breaker