| 摘要 |
<P>PROBLEM TO BE SOLVED: To switch between series connection and parallel connection and also to change rotational speed, with less number of components with no expensive tap-switching fan motor. <P>SOLUTION: The connection between fan motors 1 and 2', series connection or parallel connection, is switched by a relay 22. An MOS transistor 23 is connected in series to the fan motor 2' and it is turned off when the relay 22 establishes the series connection between the fan motors 1 and 2', while it is turned on when the parallel connection is established to supply a current to the fan motor 2'. A control circuit 24 adjusts a gate voltage of the MOS transistor 23 for controlling a drain current, resulting in variable rotational speed of the fan motor 2'. <P>COPYRIGHT: (C)2004,JPO |
