| 摘要 |
1318060 Battery charging circuits; standby supply circuits SOC DES ACCUMULATEURS FIXES ET DE TRACTION 6 Aug 1970 [7 Aug 1969] 38074/70 Heading H2H [Also in Division H3] A circuit for charging a standby battery Ba comprises a resistor Rs in the discharge circuit of the battery and a transistor stage T 3 , T 4 which allows a charging current to flow through a cell B 6 used as a memory, the discharge of the cell being used to time the switching from a high charge rate to a low charge rate of the battery Ba when a main power supply U returns. When the main supply U is present the battery Ba is charged by the output of a diode bridge rectifier D 1 -D 4 . On failure of the main supply a contactor RO is de-energized so that the battery Ba supplies a load such as emergency lights connected between terminals A, D via a contact ro 1 . The voltage developed across the resistor Rs switches on the transistor T 4 so that the battery Ba also charges the cell Bb. When the mains supply returns, the contact ro 1 opens and a contact ro 2 closes thus enabling the cell Bb to discharge through resistors R 3 , R 4 . A transistor T 1 is therefore switched on which in turn switches on a transistor T 2 thereby energizing a relay Ra and closing contacts ra to connect a resistor R 2 in parallel with a resistor R 1 . A high charging current therefore flows through the battery Ba until the cell Bb becomes discharged thereby switching off the transistor T 1 and opening the contacts ra. The charging of the battery Ba then continues with a lower charging current. |
