The EM-500-3 demonstrates the operation of an automotive charging system that is controlled via the powertrain control module (PCM). It contains a variable speed drive to allow the adjustment of engine speed by modifying the alternator input to simulate the operation of the real vehicle. The alternator can accommodate a load current of 25A to demonstrate the full load charging characteristics and allows the regulator to run at full capacity. This automotive trainer is easy to use and provides students with a safe platform to learn the correct operation and testing procedure of a PCM-controlled automotive charging system. It is also equipped with a built-in voltmeter and ammeter as well as electrical test points for electronic diagnosis and troubleshooting.