Judge by checking whether the battery voltage is sufficient. If the battery maintains sufficient power for a long time, it means that the generator has normal operating performance; turn on the ignition and do not start the car, use metal; tools to approach the generator pulley. Normally there should be an obvious magnetic attraction. After finding the car, use a multimeter to test the generator output voltage. When the throttle is applied, the voltage will increase and reach a maximum of approximately 14.5 V, indicating that the generator is generating power normally.
1. Look at the nameplate and the appearance of the generator. Look at which factory it was produced in, when it left the factory and how long ago; look to see if the paint on the exterior is peeling or damaged, if the model has been disposed of, etc. Determine the newness or age (quality) of thegenerator from nameplate and appearance.
2. Perform a test.
3. Ask about the time of purchase, the purpose and reason for selling the generator, find out about past repairs, what major components were replaced and ask about any problems during use, so to have a more complete vision. understanding the generator. Generator status (good or bad)
4. Connect the positive test lead of the multimeter to the armature terminal of the generator and the negative test lead to the iron. The generator armature terminal voltage. 12V generator should be 13.5~14.5V, the armature terminal voltage of 24V generator should fluctuate between 27-29V. If the voltage indicated by the multimeter is close to the voltage value from the car battery and the pointer does not move, this means that the generator is not producing electricity.