1, detected by the instrument voltage range.
Turn the multimeter knob to the DC voltage of 30V (or use a common DC voltmeter to make proper gear), connect the red stylus to the "armature" of the generator, and connect the black stylus to the housing, so that the engine can run at medium speed or above. The standard voltage of 12V electrical system should be around 14V, and that of 24V electrical system should be around 28V. If the measured voltage is the battery voltage, it means that the generator does not generate electricity.
2. External ammeter detection
When there is no ammeter on the dashboard of the car, an external DC ammeter can be used for testing. First, remove the lead wire of the generator "armature" terminal, then connect the positive pole of the DC ammeter with a range of about 20A to the generator "armature", and connect the negative pole wire to the above-mentioned removed connector. When the engine runs above the medium speed (no other electrical equipment is used), the ammeter has 3A~5A charging instructions, indicating that the generator is working normally, otherwise the generator will not generate electricity.
When the engine is running above medium speed (without using other electrical equipment):
The ammeter has 3A~5A charging instructions, indicating that the generator is working normally, otherwise the generator will not generate electricity. When there are no multimeters and DC meters, you can use car bulbs as test lights to detect.
Welding wires with appropriate lengths at both ends of the bulb, and connecting fish clips at both ends. Before the test, remove the lead of the generator "armature" terminal, and then clamp one end of the test lamp on the generator "armature" terminal, and the other end is grounded. When the engine is running at a medium speed, the brightness of the test lamp indicates that the generator is working normally, otherwise the generator will not generate electricity.
Change the engine speed and observe the brightness of the headlights. After starting the engine, turn on the headlights to gradually increase the engine speed from idle speed to medium speed. If the brightness of headlights increases with the increase of vehicle speed, the generator is working normally, otherwise it will not generate electricity. Remove the battery ground wire to see if the engine (gasoline engine) works.
When there is no electronic device controlled by microcomputer in the car, this method can be used for detection. Control the engine above the medium speed, and remove the battery ground wire. If the engine works normally, the generator generates electricity, otherwise the generator is faulty.