| 摘要 |
<p>The present invention relates to a direct-current device for regulating the speed of a power motor, especially a universal motor equipping domestic machines. This device is characterised in that, from a direct-current power supply, it delivers a wave at the frequency inaudible to the human ear to the terminals of the universal motor. The present invention applies to regulating the speed of a universal motor used in particular in the types of machines in which the sound power has to be reduced, such as, for example, in washing machines, vacuum cleaners or fans. <IMAGE></p> |
