Abstract: A method of balancing an electronically driven air blower unit comprising a radial blower with a high-speed electronically commutated d.c. motor which drives the blower and which is of external rotor design, utilizing a balancing device into which the completely mounted air blower unit (1) can be inserted, without housing lid, and with which electrical contact (101, 102, 103; 201, 202, 203) can be made. The balancing device is provided with a control device for the motor (3, 4, 5) of the air blower unit and with a device (9) for bridging the motor electronics (10) of the air blower unit (1) itself. In order to drive the part to balanced of the air blower unit, its electromechanical transducer (3, 4, 5) is used, which for this purpose is actuated by the control device provided in the balancing device. The balancing process is essentially carried out in two compensation planes which are spaced axially from one another and are parallel with one another.

Abstract: An electric motor includes a generally tubular housing portion having an outer surface; a plurality of fixedly held support bases spaced circumferentially about the housing portion and being at a radial distance from the outer surface of the housing portion; and a plurality of elastic elements, each being secured to the outer surface of the housing portion and to a separate one of the support bases for supporting the electric motor by the housing portion and for suppressing excitation oscillations generated by the electric motor during operation thereof. The elastic elements together form a suspension system which is tuned to the excitation oscillations of the electric motor such that the natural frequency of the suspension system is less than the excitation frequency of the electric motor.

Abstract: An electronic control device for an electric motor (10), particularly an electrically commutated (EC) motor, whose motor windings (11 to 13), in order to control the winding current, are connected in series with respective control transistors (15 to 17) whose control connections are charged by control pulses which are triggered by commutation signals and which have a predeterminable pulse-duty factor (block control). At the same time, the control device varies the amplitudes of the control pulses to control and permit the operation of the control transistors (15 to 17) in their amplifying range (linear control). Block control dominates in the upper rpm range in order to improve efficiency with respect to pure linear control, and linear control dominates in the lower rpm range in order to prevent severe current peaks, and hence an increased noise development that would occur with pure block control.

Abstract: A circuit arrangement for operating a multi-phase synchronous motor includes a switching device (13) composed of semiconductor switches (14-16) for the successive connection of the winding phases (u, v, w) of the armature winding (10) to a direct mains voltage and a commutation device (21) for the actuation of the semiconductor switches (14-16) in the correct sequence by means of switching signals (S1-S3) in conformance with the rotary position of the rotor. In order to reduce commutation noise and radio interference with low circuit engineering expenditures, each control input (G) of the semiconductor switches (14-16) is preceded by an analog difference former ( 18-20 ) which receives, on the one hand, the switching signal (S1-S3) associated with the semiconductor switch (14-16) and, on the other hand, a reference signal derived from the phase sum current of the armature winding (10).