Abstract: An asynchronous motor drive comprising a transmitter (1) of position of the rotor of the asynchronous motor whose stator windings (6) are connected to an active stator current setter (22) and a reactive stator current setter (20) through a number of series-connected units which include a controlled current source (7), a phase-sensitive rectifiers unit (9), an adder (25), multipliers (17 and 18) and a phase converter (13). Inputs (11) of the unit (9) are connected to outputs of a multiphase voltage source (12) which comprises, in a series arrangement, a reference frequency setter (30), a frequency adder (31), a frequency divider (32), a phase converter (33) whose outputs are connected to the inputs (11) of the phase-sensitive rectifiers unit (9), and a controlled rotor current frequency generator (34). The generator (34) has its output connected to the input of the frequency adder (31).

Abstract: A device for controlling the shape of the strip or sheet being rolled comprises at least two sets of rollers positioned in pairs on both sides of the strip or sheet across the width thereof and incorporating speed actuators for tensioning said strip of sheet, a reglator means for regulating the tension of the rolled strip or sheet, having its inputs electrically connected to the actuators from which output signals representative of a predetermined initial virtual tension of the strip or sheet being rolled are applied thereto, a means for setting a predetermined tensioning of the strip or sheet being rolled, said tension setting means being connected to the other input of the strip or sheet tension regulating means having its output electrically connected to the control inputs of the actuators, sensor means for sensing angular position of the rollers, and a comparator having its inputs connected to the outputs of the sensor means for sensing the angular position of the rollers and its output to other control i

Abstract: There is provided hydraulically-operated work roll gap control cylinders forming a closed-circuit hydraulic system during rolling, and there are also provided hydraulically-operated backup roll control cylinders to which is connected a rolled product thickness gauge in order to keep constant the work roll gap depending on the pressure existing in the closed-circuit hydraulic system. The apparatus is provided with a hydraulic volume compensator operating in conjunction with the closed-circuit hydraulic system of work roll gap control and is also provided with a logic module connected to said compensator. The volume of fluid contained in the closed-circuit system changes in response to the corrective signal characteristic of a deviation of the strip thickness from the specified gauge. The passage of the signal to the hydraulic volume compensator is cleared or blocked by a special transportation lag unit.