| 摘要 |
<p>1,150,291. Standby supply systems. SOC. DES ACCUMULATEURS FIXES ET DE TRACTION. 2 June, 1966 [2 June, 1965], No. 24722/66. Heading H2H. An electric appliance is fed normally from A.C. mains and on mains failure from an emergency source comprising a battery fed electronic inverter which remains blocked during normal mains operation by a voltage obtained from rectification of the mains, but is not permitted to operate when this voltage disappears unless a second voltage obtained by rectification of the voltage applied to the appliance was present immediately before the mains failure. The appliance e.g. a fluorescent lamp 1 is fed normally through an autotransformer 2 from an A.C. supply 3, 4. From the same supply a transformer-rectifier unit 16 charges a battery 14 through a resistor 24. When the transformer 2 is operating, a capacitor 43 is maintained charged, the potential from which is applied in opposition to a greater voltage across resistor 24 to a transistor or thyristor inverter 15 to prevent it oscillating. On failure of the supply the potential across resistor 24 disappears and that across the capacitor 43 sets the inverter into operation. The inverter preferably operates at a frequency substantially higher than that of the supply. A resonating capacitor 41 passes high frequencies and attenuates low frequencies, and another capacitor 13 serves the dual purpose of diverting high frequencies from the supply and also improving power factor in normal operation. Push buttons 57, 58 may operate the circuit manually.</p> |
