| 摘要 |
An emergency power circuit is designed in event of power outage to connect a battery 1 to an emergency light source 2. The battery can be connected via a connection device 3 either to a charging circuit 5, 6, 7 which is energised from a power supply network or to the emergency light source. The connection device is arranged so that, during normal power supply, it maintains the battery connected to the charging circuit. According to the invention, a time connection circuit 9 is connected to the connection device and contains at least two time control circuits 10, 11, designed to put out pulses in sequence with different pulse periods. The pulses, in turn, control a transistor 12 which interrupts the power supply to a relay 8, whereupon the charging circuit is disconnected and the battery is connected to the emergency light source. This connection is maintained for a certain determined time corresponding to a first pulse time, after which a new pulse controls the transistor so that the battery is again connected to the charging circuit and is kept in this connection for a time corresponding to a second pulse period. In this way, one has a fully automated connection of the battery to the emergency light source, which must be done with a certain determined time interval in order for the battery to retain its charge capacity. <IMAGE> |
