| 摘要 |
PCT No. PCT/SE90/00049 Sec. 371 Date Oct. 11, 1990 Sec. 102(e) Date Oct. 11, 1990 PCT Filed Jan. 24, 1990 PCT Pub. No. WO90/09138 PCT Pub. Date Aug. 23, 1990.A vacuum cleaner has an electric motor (15) and a suction fan (17) connected to the motor. A control device (16) drives the motor in a speed range limited upwards by a rated voltage corresponding to a rated power level for the motor. Circuit components (46, 39; 30, 31) are provided after actuation of a manually operable switch (19), to temporarily connect the motor (15) to a voltage exceeding said rated voltage, resulting in operation at an increased power level during a predetermined time. The circit components (46, 39; 30 31) for connecting of the increased voltage includes a thermally-operated device (46, 30) which cooperates with the control device (16) for the connection and disconnection, respectively, of the increased voltage, the predetermined time being determined by the heating time for the thermally-operated device. |
