| 摘要 |
PURPOSE:To contrive to miniaturize and lighten an AC uninterruptive power supply and to reduce its cost by improving within a range permissible on the load side the operation frequency of an inverter to be operated at the time of voltage drop or power failure. CONSTITUTION:Usually, a commercial AC power supply 1 is supplied to a rectifier load apparatus 50 via a change-over instrument 40 while a storage battery 20 is charged by a charger 10 and an inverter 30 is in a stopped state. At the time of a voltage drop or power failure of the commercial AC power supply 1, the change-over instrument 40 is switched to the inverter 30 side and starts an operation at a frequency at least higher than a commercial frequency, where the inverter 30 with the storage battery 20 as a power source is permissible on the rectifier load apparatus 50 side, to supply power continuously to the rectifier load apparatus 50 via a commercial frequency transformer 31 and an AC filter 32. Thus, the output transformer capacity of said inverter 30 and the AC filter 32 capacity can be made small so that an apparatus is miniaturized and lightened and its cost is reduced. |
