| 摘要 |
A ventilating device for rooms is provided with a fan 45 which can be influenced via a rotation speed regulator and is driven by an electric motor. In this case, the rotation speed regulator has two coils 47 and 48, which are inductively coupled to one another exclusively by means of a common core 46 which can be displaced axially, of which coils the primary coil 47 can be connected to the mains power supply by means of a switching contact 52, via a capacitor 50 and possibly a resistor 51 which is connected in parallel therewith, as a spark-extinguishing device. The secondary coil 48, together with the diode 53, a capacitor 54, at least one resistor 55a to 55c, as well as a transistor 56 and a bridge rectifier 57, forms the rotation speed control loop for the electric motor of the fan 45 (Fig. 8). <IMAGE>
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