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.