Automatic Switch Circuit Breaker:

The Automatic Switch Circuit Breaker is the simplest circuit interruption device is the knife switch. By closing the switch against the action of a spring we have an automatic device in which the energy for opening the contacts is stored by the closing operation. Such a Automatic Switch Circuit Breaker device is shown in Fig. (15.1).

Here only a small force and a short time is needed to open the switch by means of a simple latch, which when it is tripped, releases the stored energy of the spring and opens the contacts.

The switch now becomes a true circuit breaker which can interrupt the current under predetermined conditions, e.g. when la short circuit occurs or when excess current endangers the system.

This is obviously a very crude method of control and is used only in simple low voltage circuits.