🔍 Key Concepts

• Trace the field excitation path for the port propulsion motor from the 4160 VAC main switchboard all the way to the motor field winding in the illustration. • Identify which components are common/rotating on the motor shaft (cannot be replaced by an external standby source) versus which are external/control components that can be switched over. • Look closely at how the standby excitation transformer and standby field controller are connected and to which parts of the port and starboard field circuits they can be substituted.

💭 Think About

• If you switch to the standby excitation transformer and standby field controller, which original port-side component(s) are actually being bypassed or replaced, according to the diagram? • Which of the listed components would still be physically in the excitation path even when the standby system is in use, and therefore could NOT be fixed simply by switching to standby? • Among the answer choices, which component is clearly an "on-the-rotor" or motor-internal device that the standby external equipment cannot replace?

✅ Before You Answer

• Verify on the diagram which elements are labeled as standby and see exactly where they tie into the port excitation circuit. • Confirm which components (rotating rectifier, rotary transformer, motor field winding) are shown as common to both normal and standby excitation sources and therefore must remain healthy for either system to work. • Ensure that the component you choose is one that the standby excitation transformer and standby field controller can logically substitute for or take over from, based on the connection points shown.