ABSTRACT
Arc discharge is encountered in the everyday use of power equipment. Whenever a circuit breaker or a load-break switch is opened while carrying a current, an arc strikes between its seperating contacts. In air circuit breakers the arc burns mainly in an atmosphere of air; it burns mainly in hydrogen in oil circuit breakers; and it burns in composites of sulfur and fluorine in SF6 circuit breakers. The current is also carried partially by positive ions drifting slowly to the cathode from the plasma of the arc column. In the space between the surface of the cathode spot and the cloud of positive ions there is a high electric field. The arc column loses some of its charge carriers by diffusion from its surface. It also loses heat by radiation and convection. To study the arc extinction in a circuit breaker, one needs detailed information about the thermal energy of the arc, the kind of arc chamber, etc.
