HUT49007A - Method and device for switching electric circuits free from arcs - Google Patents

Abstract

The arc-free commutation device, has controlled semiconductor element e.g. transistor (9), and fixed amount movable cutbacks of n.o. contact connected across its power output, and the control current resistor (11) connected to its base. With the transistor connected as indicated, arc-free switching is achieved not only for the load network, but also for the control circuit, which additionally comprises the n.c. contact (10) of the switching contact group (I). - Initially to transistor (9) is non-conducting and functions as a junction diode, its emitter and base are shorted out by contacts (2,10). With switch-on, the movable contact (2) moves away from the fixed contact (10) thus leading to increased contact resistance of the contacts (2,10) which together with resistance of the contacts (2,10) which together with resistance of resistor (11) transfers the transistor (9) to the satn.mode. The contacts (2,10) then open, and the satd. base-emitter junction of the transistor (9) prevents sparking and arcing processes starting. Field-emission of electrons in the contact-gap of the contacts (2,10) is also prevented.