Abstract: A semiconductor device includes a sealed vessel accommodating a semiconductor body and a heating element. When the semiconductor body is not energized, the heating unit is heated.

Abstract: A converter valve which is constructed from modular elements is disclosed. Each of these modular elements comprises a group of thyristors arranged in side-by-side relationship and the drive means and circuit component group associated with such thyristor group. A metallic shield surrounds the thyristor group and its associated drive means and a portion of its associated component group. The shield, in turn, is supported within a metallic pressure tube which has both its ends closed off by bulkheads and is adapted to receive SF.sub.6 gas. The aforesaid bulkheads may be separate connecting members which, in addition, may also be designed as nodal elements and mechanical support points. The converter valve is constructed from a small number of the aforesaid modular elements, each element being replaceable without removing the gas from the entire valve.

Abstract: A gas-insulated thyristor arrangement with at least one thyristor column which is constructed of disk-type thyristors and is arranged, together with its associated drive and external-circuit modules, in a rotationally-symmetric shield which is fastened via at least one insulating standoff to the pressure tube of an electrically conductive pressure encapsulation. One end of the pressure tube is closed off by an end plate integrally formed therewith in the manner of a tank and the other end is closed off by means which includes at least one bulkhead of insulating material. The entire arrangement is filled with gaseous SF.sub.6 under pressure and detachable electrical connecting leads are extended through the bulkhead.

Abstract: A gas-insulated thyristor assembly is disclosed. The assembly comprises at least one thyristor column which includes disk-type thyristors which are arranged in side by side relationship. The assembly further includes drive and circuit component modules associated with the thyristors. In accordance with the invention, a rotationally-symmetric metallic shield surrounds the disk-type thyristors and is supported within a cylindrical metallic pressure tube by insulating posts. The opposite ends of the aforesaid pressure tube are closed off by bulkheads comprised of insulating material and the tube is adapted to receive SF.sub.6 gas under pressure. A detachable electrical connecting line is passed through each bulkhead and the pressure tube is adapted to be detachably connectable with adjoining pressure tubes.

Abstract: In a converting device having two sets of converters, each of which includes planar type semiconductor controlled rectifier elements connected in a bridge configuration, with the converters being connected to a load, in a reverse-parallel configuration, so that the anode of one element is connected to the cathode of its parallel connected element, cooling fins are interposed between the planar type semiconductor controlled rectifier elements so that an individual cooling fin serves to cool directly adjacent elements disposed along the same axis in series with each other. As a result, the number of cooling fins can be sharply reduced. The converting device is especially effective for normal and reverse switching operations of a d.c. motor.

Abstract: A frequency-changer comprising an air-cooled rotary frequency converter having a shaft which carries a rotor of a fan arranged to cool the converter by forced ventilation. The converter is located in a sound-proofed housing through which forced air flow produced by the fan is passed. The housing defines above the converter a chamber through which the air is guided to flow in the opposite direction to the air flow through the converter. The chamber has an upright baffle at each end and is divided into two compartments by a wall extending through the chamber parallel with the axis of rotation of the converter. Controls for the converter are accommodated in the compartments.