Abstract: A lift truck has a tractive-power electric motor, an electric motor which actuates a pump for the hydraulic circuits, and batteries which supply the electric motors. In order to obtain a long working life as well as reliability and a high performance, the tractive-power motor or both motors are asynchronous and there are provided devices for sensing the angular positions and angular velocities of the motors and an electronic control unit connected to the sensor devices for controlling the power supplies to the motors in dependence on required velocities for the motors and on the basis of data provided by the sensor devices.

Abstract: An electric drive system in lift trucks has, for driving the lift truck driving wheels, at least one separate excitation electric motor provided with a stator and a rotor which are energized independently of each other by means of an electronic drive and control unit; by this arrangement, space can be saved on the lift truck and the lift truck can be rendered reliable, low in running cost, adaptable to varying load conditions, and adjustable as regards its operational parameters.