In-Depth Notes on Starter Generator System Operation

Overview of Starter Generator System

• The starter generator system utilizes coils and switches for operation.

Role of Coils and Switches

• Coils energize when the ignition is activated.
• Energized coils operate fuel solenoid valve and fuel heater.
• Energizing the coil pulls a ferrous switch down, allowing power flow.

Process Flow

• Starting Sequence
• Current flows through the coils.
• Power activates the fuel solenoid valve and the fuel heater.
• Fuel Pump Activation
• Fuel pump switch turns on after the coils energize, allowing fuel to flow.
• Requires sufficient power for operation.

Undercurrent Relay

• Monitors current flow to the starter generator.
• De-energizes once engine speed reaches a sufficient level, disconnecting power from the starter generator.
• Ensures the starter circuit shuts down while allowing the generator to operate.
• Shutting down the starter includes turning off the starter switch.

Additional Components

• Ignition Relay Area
• Shuts down when the igniter is deactivated.
• Engine Master Switch
• Closing the engine master switch allows current to flow to the ignition relay and subsequently to the ignition exciters.
• Current flow enables testing of the ignition system.

Test Switch Functionality

• The test switch functions under normal conditions unless specific wires are compromised.
• If wires 14 or 15 are broken, the ignition relays will still operate but not facilitate the test switch's function.
• If disconnects occur in wires 10 or additional critical lines, the operation may indicate functionality while actual ignition does not occur.

Key Points to Remember

• The undercurrent relay plays a vital role in engine safety by ensuring power is cut to the starter at appropriate speeds.
• Ignition relay switches are crucial for system testing and may behave differently based on wiring integrity.

Preparation for Exam

• Review the functions and interdependencies of the relay system thoroughly.
• Understand how switching affects both starting and operational sequences in the generator.
• Be prepared to discuss and explain potential failures in the system and their implications on ignition and start-up processes.