Abstract: An apparatus for controlling the power of an AC voltage supplying an electrical consumer (14) by phase control and for reducing harmonics caused by said phase control, particularly within a range of 4 kHz, preferably within a range of the third harmonic, comprising a first switching element (12) (TRIAC) connected in series with the consumer (14) and driven by a control device (20) for performing a phase control. A second switching element (34) connected in series with a resistor element (32) is provided in parallel to the first switching element (12). The control device (20) is adapted to drive the second switching element (34) shortly before the first switching element (12) into its conducting state for a short time period.

Abstract: The invention relates to an apparatus for power control by phase gating of an AC voltage, which supplies an electrical load (14), and for reduction of harmonics which are created by the phase gating, in particular up to a region of 4 kHz, preferably in the region of the third harmonic, having a first circuit element (12) (TRIAC) which is connected in series with the load (14) and is driven by a control device (20) in order to carry out phase gating. The apparatus is distinguished in that a second circuit element (34) is provided in series with a resistance element (32), with the series circuit being arranged in parallel with the first circuit element (12) and with the control device (20) being designed such that it drives the second circuit element (34) shortly before the first circuit element (12) and switches it to the on state for a short time period. The invention also relates to a method for harmonic reduction in the range up to 4 kHz, preferably of the third harmonic, for power control by phase gating.

Abstract: A method and arrangement for controlling the output of electrical consumers connected to ac line voltage, especially of electric motors and the like, in which the output is changed by changing the phase control of the electric alternating magnitude supplied to the consumer. The extent of the firing angle determining the extent of the phase control is varied toward larger or smaller values around the given reference value of the firing angle, which reference value corresponds to the desired power consumption, so that asymmetry of the firing angle is produced with respect to time between two successive full waves, whereby odd-numbered harmonics are sharply reduced as even-numbered harmonics slowly increase.

Abstract: A method for controlling the output of electrical consumers connected to ac voltage, especially ohmic loads such as hot-plates, fans, hot-air blowers, electric heaters and the like, wherein an electric or electronic circuit component which conducts ac voltage in both directions, preferably a triac, is connected in series with the consumer, and the output control is effected at the consumer by the given angle of the phase control. An additional electric or electronic circuit component is arranged in parallel to the first series switching element, however, the additional component is controlled first so as to conduct in a controlled manner at the trigger time determined by the device control. The current flow of the additional component is substantially taken over by the first circuit component at the latest when reaching a predetermined threshold current through the load or a threshold voltage at the load or triac.

Abstract: In an apparatus for regulating the power consumption of a vacuum cleaner, it is proposed to detect the pulsating alternating current present at the driving electric motor and delivered by a phase-angle circuit by means of a parallel voltage sensor, rectify it, smooth it, digitize it, and, on the basis of data stored in tabular form from a memory arranged in a microprocessor, convert it into a true effective value of the motor voltage; and subsequently to compare it with various associated respective manually defined power data and to activate the phase-angle circuit so that irrespective of fluctuations or different power system alternating voltages or frequencies, motor output is regulated to constant values corresponding to the manual setting.