Abstract: A mounting structure of a semiconductor converter comprising a frame and circuit components including a first group of circuit components which almost need not a cooling except for a semiconductor element, and a second group of circuit components which requires a cooling, in which the first group of circuit components such as a gate turnoff element, a thyristor, a snubber capacitor, a snubber diode, a gate circuit, a by-pass diode, a fuse and a heat sink is arranged in units on a front side of the frame, and the second group of circuit components such as a snubber resistor and an anode reactor is arranged within the frame behind the units.

Abstract: In a heat sink for semiconductor elements and the like, a pipe made of a heat-conductive material such as copper, aluminum and the like is bent at a middle portion thereof and wound such that a forward flow passage and a return flow passage for a liquid coolant are both formed into a spiral shape with the bent portion held at the center of the spiral.

Abstract: An enclosed thyristor valve of the type dividable into first and second portions comprises a tank, a thyristor valve assembly including a plurality of thyristor elements encased in the tank, a plurality of light guides extending through the tank for transmitting light signals for firing the thyristor elements, cooling pipes extending through the tank for circulating a coolant to cool the thyristor assembly, and bushings mounted on the tank for connecting the thyristor valve assembly with a power line system. The first and second portions are connected at mating flange portions disposed to the first and second portions of the tank. The light guides and cooling pipes are provided for the first portion of the tank so that the light guides and the cooling pipes are not disconnected from the first portion when the inspection and the maintenance of the thyristor valve are required.

Abstract: In a water-cooled high voltage device, a plurality of electrical modules are divided into a plurality of electrical units. The electrical modules are cooled by cooling water supplied from a pump through pipes which are disposed in the electrical units, respectively. The size of the pipe diameter is determined to be enough to allow cooling water to flow at a relatively low pressure and to properly cool the electrical modules.