| 摘要 |
In the operation of signalling boxes, the power is fed to the relays controlling the light signals of the external system from a rectifier or from the battery of the signalling box when the mains power fails. If the power supply for the external system fails, the monitoring contacts arranged in the control circuits of these relays change over. This would lead to the relay being released and thus would lead, inter alia, to route cancellations when the power supply is resumed. In order to avoid this, the switching state of the control relays which is respectively present when the power supply fails is stored until a battery-operated standby power supply or a mains replacement unit can take over supplying power to the light signals. As soon as this has happened, it must be ensured that the switching state of the control relays is made exclusively dependent again on the switching state of the control switching means, for example the switching state of the lamp monitors, arranged in their control circuits or holding circuits. If this did not take place, the actuating elements for the signals at go would remain excited and the associated light signals would show a signalling concept even if the section covered by these signals were in the meantime occupied. The circuit according to the invention ensures that the status of the information of the signalling circuit which is current before the failure of the supply voltage is maintained until, after the predetermined connection time of the standby circuit, the connected loads (e.g. ... Original abstract incomplete. <IMAGE>
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