How is testing an alternator typically conducted?

Testing an alternator is most effectively conducted by checking its output voltage and current under load. This process is crucial because it simulates real-world operating conditions, allowing for an accurate assessment of the alternator's performance. When an alternator is subjected to a load, it must produce adequate voltage and current to power the vehicle's electrical systems and recharge the battery. By measuring these outputs while the alternator is under load, technicians can evaluate its efficiency and identify potential issues such as inadequate power generation or excessive voltage drop, which may indicate wear or failure.

Alternative methods like examining the alternator for physical damage, comparing it with a new unit, or measuring its weight may provide some insights but do not give a comprehensive assessment of the alternator's functionality. Physical damage might indicate issues, but it doesn’t measure performance. Comparing with a new unit doesn’t account for different operational conditions and can lead to misleading conclusions. Measuring weight is not relevant to the alternator's performance or its ability to generate power. Thus, testing under load is the most reliable and informative method for evaluating alternator functionality.