Abstract: An object of the present invention is to provide a water electrolyzer, which has higher electrolyzing efficiency and smaller size than conventional ones. In an electrolyzing tank, at least three cylindrical electrodes, each of which has different polarity with respect to adjacent one, are arranged concentrically with cylindrical partitions. Surface area of the one cylindrical electrode, which is provided between other two, is equal to the sum of surface area of an outer face of the inner cylindrical electrode and that of an inner face of the outer cylindrical electrodes, so that maximum electrolyzing efficiency can be gained.

Abstract: In the water electrolyzer, an electrolyzing section has electrodes for electrolyzing raw water. The water pressure sensor detects pressure of raw water introduced into the electrolyzing section. A driver circuit adjusts electric power supplied to the electrodes. A microprocessor controls the driver circuit to adjust electric power supplied to the electrodes on the basis of water pressure detected by the water pressure sensor so as to maintain the pH value of the electrolyzed water in a prescribed range. With this structure, the pH value of the electrolyzed water can be maintained in the prescribed range without reference to quantity of water in the electrolyzing section.

Abstract: A railway vehicle has a plurality of motors for driving a plurality of wheels respectively, which motors are controlled to produce the same current to attain the same torque for each motor. These current values are detected respectively and received alternately in time division manner. A current value received is stored until the next current value for the same motor is received. The current value newly received is compared with the immediately previously stored current value for the same motor and the error therebetween is detected. When the current variation for the motor is larger than a predetermined value, the slipping of the wheel driven by that motor is detected. Also a received current value is compared with the current values for the other motors, and if the error is larger than a predetermined value, the slipping of the wheel driven by the motor associated with the received current value is detected.

Abstract: A power converter which can operate with both a D.C. power source and an A.C. power source for supplying electric power to a D.C. load such as a D.C. motor. The power converter comprises thyristors, a diode, a reactor and a capacitor. A plurality of series circuits each including two series-connected thyristors are connected in parallel to provide A.C. terminals at the series connection points of the thyristors and to provide D.C. terminals at the parallel connection points of the series circuits. The diode is interposed between the parallel-connected series circuits of the thyristors, and the reactor and the capacitor are connected in series to form a series circuit which is connected in parallel with the series circuits of the thyristors. The power converter is connected at the D.C. terminals between the power source and the load to function as a chopper when the power source supplies D.C. power to the load. On the other hand, when the power source supplies A.C.