Bulk oil circuit breaker diagram. Large quantity of oil is necessary in oil circuit breakers though only a small quantity is necessary for arc extinction. Bulk oil circuit breaker bocb the bulk oil cb design is very simple fig a. In fig a the arc control device between the fixed and moving contacts is not shown so making the sketch even simpler. In a minimum oil circuit breaker the interrupter is enclosed in an oil filled chamber at live potential.
Such type of circuit breaker is also known as dead tank type circuit breaker because their tank is held at ground potential. In the bulk oil circuit breakers the oil serves as both arcs extinguishing medium and main insulation. Bulk oil circuit breaker construction of bulk oil circuit breaker. The basic construction of bulk oil circuit breaker is quite simple.
It consists of two oil filled chambers namely upper chamber and lower chamber which are separated from each other. Construction of oil circuit breaker. This type of circuit breaker uses a steel tank containing oil and the contacts are immersed in the oil. A low oil circuit breaker employs solid materials for insulation purposes and uses a small quantity of oil which is just sufficient for arc extinctionas regards quenching the arc the oil behaves identically in bulk as well as low oil circuit breaker.
A breaker which uses a large quantity of oil for arc extinction is called a bulk oil circuit breaker. It consists of current carrying contacts enclosed in a strong weather tight earth metal tank and the tank is filled with transformer oil. The insulating oil is available only in interrupting chamber. Figure 19 schematic diagram of bulk oil circuit breaker.
A plain break oil circuit breaker is a bulk oil circuit breaker which involves the simple process of separating the contacts under the whole of the oil in the tank. Low oil circuit breaker. Bulk oil circuit breaker. The oil is utilized primarily as the interrupting media unlike in a bulk oil circuit breaker where the oil is utilised as an insulating media as well.
The features of designing mocb are to reduce requirement of oil and hence these breaker are called minimum oil circuit breaker. There is no special system for arc control other than the increase in length caused by the separation of contacts. Oil circuit breaker is very easy in construction.