What is the function of the alternator?

What is the function of the alternator?

• A. 24 volt, used to start diesel engine
• B. Routes engine exhaust
• C. Provides electrical current to replace current being drawn from the battery
• D. Removes solid contaminants from engine oil

Answer: (C)

The function of the alternator is to replace the electrical current being drawn from the battery and to keep the battery charged while the engine runs. When the engine is running, the alternator is belt-driven and generates electricity. That power is first used to run the vehicle’s electrical systems (lights, radio, ignition, sensors, etc.) and the rest goes to recharge the battery. The alternator provides DC current after a rectifier converts the generated AC, and a voltage regulator keeps the system voltage at the proper level (typically around 13.8–14.4 volts for a 12-volt system). If electrical loads rise, the alternator ramps up output to prevent the battery from discharging; if there are no loads, it still maintains the battery’s charge. The other options describe functions that belong to other parts: starting a diesel engine uses the starter motor, routing exhaust is the exhaust system, and removing contaminants from engine oil is done by a filter.

The function of the alternator is to replace the electrical current being drawn from the battery and to keep the battery charged while the engine runs. When the engine is running, the alternator is belt-driven and generates electricity. That power is first used to run the vehicle’s electrical systems (lights, radio, ignition, sensors, etc.) and the rest goes to recharge the battery. The alternator provides DC current after a rectifier converts the generated AC, and a voltage regulator keeps the system voltage at the proper level (typically around 13.8–14.4 volts for a 12-volt system). If electrical loads rise, the alternator ramps up output to prevent the battery from discharging; if there are no loads, it still maintains the battery’s charge.

The other options describe functions that belong to other parts: starting a diesel engine uses the starter motor, routing exhaust is the exhaust system, and removing contaminants from engine oil is done by a filter.