Abstract: The invention relates to a method for the open-loop or closed-loop control of an asynchronous machine with or without speed feedback, the asynchronous motor being controlled by a control device (converter or servo converter). First of all, a voltage vector rotating at a rotary field frequency is specified and impressed, both the rotary field frequency and the voltage vector being determined by an open-loop or closed-loop control based on a voltage-frequency characteristic curve configured in any manner and the voltage vector being adapted by a cos ? closed-loop control. Desired values of cos ? are calculated using rating plate data and equivalent circuit diagram data for an optimum-loss or loss-optimized operation of the asynchronous machine for the calculation of cos ?desired value, which results in optimized-loss operation. A value for cos ?actual is then determined using the impressed voltage vector and a current vector or using the real power and apparent power.

Abstract: The invention relates to a method for the open-loop or closed-loop control of an asynchronous machine with or without speed feedback, the asynchronous motor being controlled by a control device (converter or servo converter). First of all, a voltage vector rotating at a rotary field frequency is specified and impressed, both the rotary field frequency and the voltage vector being determined by an open-loop or closed-loop control based on a voltage-frequency characteristic curve configured in any manner and the voltage vector being adapted by a cos ? closed-loop control. Desired values of cos ? are calculated using rating plate data and equivalent circuit diagram data for an optimum-loss or loss-optimised operation of the asynchronous machine for the calculation of cos ?desired value, which results in optimised-loss operation. A value for cos ?actual is then determined using the impressed voltage vector and a current vector or using the real power and apparent power.

Abstract: A bending mandrel arrangement for use in a machine for the simultaneous bending of a plurality of parallel reinforcing rods for concrete comprises a work support beam on which the rods rest, a trackrail mounted on said work support and having an upper open grooveway and a vertical wall, a plurality of mandrels having arms which engage in said trackway and abut said vertical wall so that the mandrel arms can be simultaneously urged into clamping engagement with said trackrail, and a bending bar which is movable around said mandrel arms to bend said rods.

Abstract: A cutting apparatus for cutting steel rod into predetermined lengths. The apparatus has a feed track and a discharge track at opposite sides of a shearing unit, the discharge track having a number of stops which may be located at selected spacings. The shear unit is adjustable between the tracks whereby an adjustable intermediate track is located between the shear unit and the entry to the discharge track according to the position of the shears.

Abstract: A holddown device for retaining material in place to be sheared, which holddown device includes a longitudinally movable beam that is resiliently maintained in its operating and starting positions, which resilient arrangement precludes breakage of the elements employed to position the beam during its various movements.