| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply system capable of attaining high efficiency and a long life cooling fan. <P>SOLUTION: The uninterruptible power supply comprises a main inverter 12 that provides AC power to a load 52 and also a sub-inverter 24 that provides AC power to a cooling fan 26, which controls a rotational speed of the cooling fan 26 to prevent a temperature T in a housing 1 from exceeding a predetermined temperature T0, when a load current I is larger than a threshold current Ith. When the load current I is smaller than the threshold current Ith, the cooling fan 26 is driven intermittently. And if the sub-inverter 22 is failed, the AC power will be provided to the cooling fan 26 from an AC power supply. Therefore, the efficiency of the uninterruptible power supply system becomes higher and the life of the cooling fan 26 becomes longer than that of the conventional art in which the cooling fan 26 is driven always at a rated speed. <P>COPYRIGHT: (C)2012,JPO&INPIT |
