Abstract: A drive system with slip control for railway vehicles with two or more dc drive motors and with common control of the motor armature currents and a logic unit to which are input a measured signal which indicates the armature current intensity of the motor driving the axle having the best adhesion which is usually the trailing axle motor. The measured signal and an amplification signal are multiplied by each other and the product signal issued in a feedback loadsharing system to control the other motors such that the torque of the other motors increased to a maximum allowed level, the trailing axle then rolling very close to ground speed without slipping. This speed is used as a measure of the true speed, which in turn controls the system for loadsharing such that the vehicle can be controlled to maximum tractive effort without causing slipping axles.

Abstract: A static electrical converter equipment has a plurality of controllable converter bridges connected to a common a.c. supply source. Control pulse devices supply control pulses to the controllable valves of the bridges. The converter equipment comprises members arranged to prevent a control pulse from being supplied to a valve in one of the bridges, for initiating a commutation in this bridge, until a corresponding commutation in another bridge is completed.