As shown in the wiring diagram of the semi-automatic navigation lighting panel circuit, what would cause the buzzer to sound and for the indicator light to illuminate in the line section for a particular navigation running light? See illustration EL-0108.
• Trace how power flows from the ship’s supply, through the 10 A master fuses, then through the 3 A line fuses to the running light and the trouble relay coil. • Notice how the trouble relay is drawn with contacts "shown with coil de-energized" and how its contacts connect to the indicator light and buzzer bus in the line section. • Think about which components, if opened or turned off, would still allow power to reach the alarm circuit while interrupting current to the running light itself.
• For each choice, ask: does this condition remove power from the entire panel, or only from one specific running-light branch? • Look at what happens to the trouble relay coil in each case: is it energized or de‑energized, and what do its contacts do to the buzzer and indicator light in that state? • Consider whether a switch being in the OFF position would prevent the alarm from receiving power, or just the running light.
• Verify which side of the 10 A master fuse and master switch the buzzer and line‑section indicator circuits are connected to. • Check whether the transfer switch OFF position disconnects the relay coil from power, or only the lamp load. • Confirm what happens to the relay coil and its contacts if a 3 A fuse in that line section is open: does this change only that line, or the whole system?
No comments yet
Be the first to share your thoughts!