FAA Powerplant Written Practice Test

What happens when a starter solenoid is energized in automatic starting systems?

1. It cools down the motor

2. It allows current flow to the starter motor

3. It connects the battery to the alternator

4. It starts the ignition system

The correct answer is: It allows current flow to the starter motor

When the starter solenoid is energized in automatic starting systems, it allows current to flow to the starter motor. The solenoid acts as a heavy-duty switch that connects the battery to the starter motor when it receives an electrical signal, usually from the ignition switch. This connection enables the necessary current to flow, powering the starter motor, which then turns the engine over to initiate the starting process. This action is critical because without the solenoid, the starter motor would not receive the high current needed to operate, leading to the inability to start the engine. The solenoid also performs a safety function by isolating the battery circuit from the starter motor when not in use, preventing accidental engagement. The other options address components or functions that are not directly related to the specific action of the starter solenoid when energized. Hence, the correct understanding of the starter solenoid's role is essential for comprehending the process of engine starting in automatic systems.