Hitachi, Ltd.

Tomio Tadokoro

Akio Sasaki

Toshikatsu Kouno

Tatsuro Horie

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.

Slipping detector system for vehicles

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. power to the load, the power converter is connected at the A.C. terminals to the power source and at the D.C. terminals to the load to function as a converter or inverter. The desired function of the power converter is obtained by controlling the gate signal applied to the gate of each of the thyristors.

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Katsuta, Japan

Tomio Tadokoro