| 摘要 |
PROBLEM TO BE SOLVED: To provide an uniterruptible AC power unit which is free from backup defects due to failures or the service life of an energy-storing means by eliminating unnecessary discharging of the energy-storing means. SOLUTION: An uninterruptible AC power unit is provided with a main circuit 9 and a by-pass circuit 11, both of which are connected to AC input power 1 and a load 3 and a serial circuit composed of an inverter 16 connected to the main circuit 9 and an energy-storing means 17. The power unit is characterized in that a means is provided with an abnormal synchronization detecting means 21 which detects synchronization abnormality caused by the inverter 16, and when the means 21 detects abnormal synchronization, the unit is controlled so as to supply a load current through the by-pass circuit 11. |
