Ebm Elektrobau Mulfingen Gmbh & Co.

Karl-Heinz Schultz

Helmut Lipp

Wilhelm Reinhardt

Wilhelm Reinhart

The invention pertains to a control circuit for a collectorless DC motor where at least one power transistor (14, 16) is input-connected to each stator coil (2, 4) of the motor; said transistor is driven by at least one rotor position sensor, especially a Hall generator having commutation circuits to commute the motor current, and where a blocking protection device is provided to interrupt the motor current in an overload or blockage. The blocking protection device (26) has at least one semiconductor circuit (30) carrying the motor current which is switched through or blocked depending on its temperature.

Trigger circuit with blocking protection device for a collectorless DC

Method and apparatus for driving an alternating-current motor. A sinusoidal supply AC voltage is rectified into a pulsating, unsmoothed DC voltage, with sinusoidal half waves and from this DC voltage an alternating-current motor voltage is produced by means of controllable polarity reversal. The pulse width of this alternating-voltage of the motor can be modulated. The polarity reversal takes place in accordance with the supply frequency in such a way that the AC voltage of the motor is essentially composed of the sinusoidal half waves of the pulsating DC voltage. For this purpose, the motor speed can be altered by changing the AC voltage of the motor with a constant timing frequency, lying outside the range of audibility, into pulse-width modulatable voltage pulses.

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Ohringen-Cappel, Germany

Karl-Heinz Schultz