Abstract: An arrangement for energy economy in a drive which includes an induction motor and a clutch-brake unit, particularly for sewing machines is provided. The windings of the induction motor are dimensioned so that the motor speed remains virtually constant in a stable speed range under normal service conditions, and in which the clutch-brake unit serves to control the drive output speed, so that the motor operates in an alternation of load phases and no-load phases. Switches are included in the current paths of the windings, which reduce the current through the windings to a prescribable degree. A modulation circuit to control the acceleration of the motor speed and its persistence in the stable speed range during load variations is associated with the switches. The modulation circuit contains a delay element, which is triggered when the mains voltage is applied, and an impulse prolongation element having a time constant dimensioned so that the motor remains in the stable speed range under all service conditions.

Abstract: An apparatus for the control of variable speed electrical positioning drives, especially for sewing machine positioning drives, is disclosed in two exemplary embodiments. The apparatus provides a preset nominal value of speed and a range of adjustment for additional signals in digital form, thus making possible a continuous or incremental change in the nominal value as well as additional digital signals. The apparatus includes lamellar contact elements of a potentiometer arranged on a base element in the path of a slider for the nominal value of speed and at least one low resistance lamellar contact element arranged in the slider path for producing an additional digital signal.