Abstract: The flame-proof electric device includes a flame-proof partition separating a flame-proof lead-in chamber for the current conductors and power supply cable and a flame-proof component chamber. The flame-proof partition has mounted thereon an interlocking disconnecting switch, a flame-proof casing and at least one first, at least one second and at least one third lead-through current-conducting terminals. The first lead-through current-conducting terminal is connected with the power supply cable and the interlocking disconnecting switch which is also connected through a serial connection of the third and second lead-through current-conducting terminals with the components of the electric circuitry within the flame-proof component chamber.

Abstract: A device has a communication line leading to a control desk and a power supply connected to the communication line. Connected to the power supply are two circuits each comprising a unit for testing the communication line for condition and a current amplifier which are connected in series with each other. Connected to the inputs of each current amplifier is an interference suppression unit having its input connected to a current comparison unit. Two current comparison units are connected to the power supply and an electrical apparatus being controlled. The device also has a logical circuit connected to the power supply and the test units and an actuating unit connected to the logical circuit and one of the test units and coupled to the electrical apparatus.

Abstract: An explosion-proof electrical unit comprises an explosion-protected chamber for leading-in current conductors and an explosion-protected equipment chamber divided by a blast-resistant wall, and through current conducting terminals secured on the blast-resistant wall. The current conducting part of each terminal inlcudes at least two elements, of which one such element is movable. In one extreme position of the movable element this movable element and the fixed element are electrically closed, whereas in the other extreme position of the movable element they are open. A cavity formed between the movable and fixed elements of the current conducting part of each through terminal is explosion-protected.