What are the methods to test if a generator is not producing electricity?

[McRicardo]

When suspecting that the generator is not producing electricity, you can test it on the vehicle without disassembling the generator to determine if there is a fault. The testing methods are as follows: 1. Voltage test: When the engine is running, set the multimeter knob to the DC voltage 30V range at the battery terminal. Connect the red probe to the generator's "armature" terminal and the black probe to the casing. Run the engine at medium speed or higher. The standard voltage for a 12V electrical system should be around 14V, while for a 24V system, it should be around 28V. For small cars, the measured voltage is usually above 13.8V, often reaching over 14V. If the generator is not producing electricity, the voltage will drop significantly after starting, often falling below 12V. If the measured voltage is the same as the battery voltage, it indicates the generator is not producing electricity. 2. External ammeter test: If the car dashboard does not have an ammeter, you can use an external DC ammeter for testing. First, disconnect the "armature" terminal wire of the generator, then connect the positive terminal of the ammeter (with a range of about 20A) to the generator's "armature" and the negative terminal to the disconnected wire. When the engine runs at medium speed or higher, if the ammeter shows a charging indication of 3A~5A, the generator is working normally; otherwise, it is not producing electricity. 3. Test lamp method: If you don't have a multimeter or a DC ammeter, you can use a car bulb to make a test lamp. Solder wires of appropriate length to both ends of the bulb and attach alligator clips to the ends. Before testing, disconnect the "armature" terminal wire of the generator, then clip one end of the test lamp to the generator's "armature" terminal and the other end to the ground. If the lamp lights up when the engine runs at medium speed, the generator is working normally; otherwise, it is not producing electricity. 4. Changing engine speed and observing headlight brightness: After starting the engine, turn on the headlights and gradually increase the engine speed from idle to medium speed. If the headlights' brightness increases with the speed, the generator is working normally; otherwise, it is not producing electricity. 5. Removing the battery ground to check engine operation: If the vehicle does not have microcomputer-controlled electronic devices, you can use this method for testing. Run the engine at medium speed or higher, then disconnect the battery ground wire. If the engine continues to run normally, the generator is producing electricity; otherwise, the generator is faulty.