摘要 |
An electrical system for use on aircraft and including a manually operated master switch for connecting a d.c. power supply to a supply bus that feeds electrical equipment on the aircraft. Energized by the supply bus is a monitor having a delayed output that activates an alarm indicating a closed condition of the master switch. The monitor is disabled by a sensing circuit that responds to the presence of electrical pulses generated on the bus by the aircraft's alternator. Upon a failure to open the master switch after the aircraft's engine has been stopped, the absence of alternator charging pulses on the bus prevents the sensor from de-activating the monitor which after a predetermined time delay energizes the alarm to warn the pilot of the condition that would result in discharging of the battery.
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