Bulk Oil Type Breaker
In Bulk Oil Circuit Breaker oil serves a two-fold purpose, i.e., as means of extinguishing
This is the oldest amongst
the three types having been developed towards close
As the power systems began
to develop resulting in higher voltages and higher
Various methods of
controlling the breaking process were investigated and developed.
Many oil Circuit Breakers
feature special arc control devices most of which are based
Depending on the working
principle of these special pressure chambers
For general illustration,
a view of the contact actuating mechanism of 33 kV,
The contacts are actuated
by a lever assembly L housed within the top-plate
The beam lever assembly is pivoted on a shaft H fixed in bearings in the top-plate and is operated by a tie rod G connected by an adjustable coupling J to the vertical pull-rod K from the Circuit Breaker operating
mechanism. An oil seal F
is fitted to prevent leakage from top-plate and an indicator arm is
operated by a pin E on the driven end of the beam lever. The lifting
bridge N which carries the lift rods Q and moving contacts R moves
vertically on guide I, rods
fixed in the top-plate, At
the top end of each guide rod and fastened to the top plate by clips
is an accelerating spring
These parts carry the arc current and protect the normal current carrying parts from burning. The moving contacts are clamped by pinch bolts at each end of a cross bar which is bolted to the lift rod.
The separation of the contacts and drawing out of the arc take place in the interrupter pot which almost completely restricts the movement of the oil within it.
The internal space available for gas is thus little more than that swept out by the moving contact, and a pressure is set up which depends upon the rate of gas production and its rate of flow through the vents.
The pressure rise and the condition resulting there from are believed to play a large part in giving this type of oil Circuit Breaker a very much higher breaking capacity than the plain break type.