Abstract: A data medium is driven by a brushless direct current motor and possesses control signals on a track which can be picked up by a sensing device and supplied to a switch arrangement for activation of the motor winding. The control signals on the track characterize at least those angular positions of the rotor with respect to the stator in which commutation is to be initiated.

Abstract: The invention relates to methods and arrangements for actuating electromechanical transducers, in particular electric motors (3) having a voltage or a current, the optimum curve shape of which is previously determined from the data of a model transducer and which data are stored in a function memory (30). In this way, a prescribed power or torque characteristic, for example without fluctuations, can be achieved.

Abstract: A circuit for controlling a d.c. motor (10) is provided with a current-limiting arrangement (27), designed as a time-delay amplifier, responding at a certain current value by interrupting the supply of current to the motor (10), and then after a certain time, determined e.g. by internal timing elements (46, 47, 49, 54), switching the current supply to the motor (10) on again. The switching operations occurring in such a motor, i.e., the pulse-duration/pulse-gap ratio and the pulse repetition frequency, are a function of the back-EMF that is induced in the motor (10) as a result of its rotation. This situation is exploited for the following purpose: to make the threshold value of the current-limiting arrangement high when the pulse-duration/pulse-gap ratio is high, namely e.g.

Abstract: An axial flow fan for ventilating electrical and electronic equipment includes a brushless, DC external rotor-type central drive motor. The stator is supported by a bearing tube formed of plastic, which is connected together with a mounting flange to form a single piece.

Abstract: A low noise brushless dc motor has a rotor with a permanent magnet and a stator with a bearing system mounting a shaft for rotating the rotor. The motor has an operating circuit that includes a tachometer winding connected to the base of a first transistor whose collector is in series with a first resistor. The other end of the tachometer winding is connected to the base of a second transistor whose collector is in series with a second resistor.

Abstract: A method for the low-loss regulation of a collectorless direct current motor and a semiconductor circuit has, during the commutation phase given by a position sensor and with reduced motor output and number of revolutions, transistors or one end transistor which initially operates temporarily as a switch and thereafter operates temporarily as an analog amplifier element. During the analog period, a current is available which changes slowly according to a ramp function.