🔍 Key Concepts
• Trace the power path from the gas turbine generator through contactors labeled A1, G1, and G2 to the propulsion armature loop feeding both propulsion DC motors.
• Trace the power path from the auxiliary diesel generator through contactors labeled A2 to the bow thruster DC motor only, without energizing the main propulsion loop.
• Understand which contactors (S1, S2) appear to be associated with the main diesel propulsion generators (#1 and #2 M/E) and what must happen to them when those engines are to be secured.
💭 Think About
• On the diagram, if the main propulsion diesel generators are shut down, which contactors must be open so that their DC generators cannot feed the propulsion motors?
• Looking only at the gas turbine generator, which contactor(s) must be closed so its output can reach the propulsion armature loop, and which must stay open so it does NOT feed the bow thruster?
• For the auxiliary diesel generator, which contactor(s) must be closed for its output to reach only the bow thruster branch, and which contactor(s) must stay open so it does NOT backfeed the propulsion loop?.
✅ Before You Answer
• Verify which bus sections or lines are controlled by A1 versus A2, and where they physically tie into the bow thruster and propulsion armature loop.
• Confirm that when #1 and #2 M/E are secured, contactors associated with their DC generators (S1, S2, G1, G2, as applicable) are not allowing power flow from those machines.
• Double-check that in your chosen option, the gas turbine path is the only one connected to the propulsion DC motors, and the auxiliary diesel path is the only one connected to the bow thruster DC motor.