Vehicle generator does not generate electricity detection method

The engine is a machine that can convert other forms of energy into mechanical energy. It was first born in the United Kingdom. Therefore, the concept of the engine is also derived from English. Its original meaning refers to the kind of "mechanical device that generates power." Its function is to convert the chemical energy of a liquid or gas into heat energy through combustion, and then convert the heat energy into mechanical energy through expansion and output power externally.

The power of the car comes from the engine, and friends who are driving are no strangers to the car engine. When we suspect that the generator is faulty, we will often conduct preliminary tests on the vehicle. If it is still impossible to solve it, we must remove the engine and perform a one-step inspection. The tools used in the test can be multimeters (voltage, resistance files), general DC voltmeters, DC ammeters, and oscilloscopes. They can also be used to test light bulbs and flashlights, and can also be tested by changing the state of the car. The following small series introduces several methods for detecting engine failures.

Car detection method

When it is suspected that the generator does not generate power, it may be detected on the vehicle without dismantling the generator, and it is roughly judged whether there is a fault.

1 multimeter voltage file detection

Turn the multimeter knob to the DC voltage 30V (or use the appropriate DC voltmeter as appropriate), connect the red meter to the “armature” of the generator, connect the black meter to the housing, and let the engine run at medium speed, 12V electrical system The voltage standard value should be around 14V, and the voltage standard value of the 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 test

When there is no ammeter on the car dashboard, an external DC ammeter can be used to detect. First remove the “armature” connection pole of the generator, and then connect the positive pole of the DC ammeter with a measuring range of about 20A to the “armature” of the generator. Connect the negative lead to remove the connector. When the engine runs above mid-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.

3. Test light (car light bulb) method

When there are no multimeters and DC meters, a car light bulb can be used as a test light to detect. Fit the ends of the bulb with appropriate lengths of wire and attach the squid clips at both ends. Before testing, remove the wires of the “armature” connector of the generator and then clamp one end of the test lamp to the “armature” connection column of the generator and the other end to ground. When the engine is running at medium speed, the test lamp brightness is indicated. The generator is working properly, otherwise the generator will not generate electricity.

4 change the engine speed observation headlight brightness method

After starting the engine, turn on the headlights to gradually increase the engine speed from idle speed to medium speed. If the brightness of the headlights increases with the increase of the speed, it means that the generator works normally, otherwise it does not generate power.

5. Remove the battery to see if the engine works

When there is no computer control electronics on the vehicle, this method can be used to detect. To control the engine at a medium speed or higher, remove the battery ground wire (usually disconnect the control main switch on the battery ground wire). If the engine is working properly, it means that the generator will generate power, or the generator will malfunction.

Car does not disintegrate detection and judgment

After removing the generator from the vehicle, you can use the following method to check and further determine the fault.

1. Flashlight bulb judgment

The two ends of the light bulb are connected with wires to make a small test light, which is connected between the generator “armature” and the housing. Connect the positive and negative poles of the battery (or dry batteries with the same voltage) to the two magnetic field connectors “F1” and “F2” of the generator (connecting the alternator with “F” and “Ground”) ), let the battery to the generator excitation. Rotate the engine belt pulley quickly by hand. The small test light shows that the generator is working normally, otherwise the generator will not generate electricity.

2. Multimeter voltage file judgment

Let the battery to the generator excitation (wiring method with the hand bulb judgment), the multimeter is selected in the DC voltage 3-5V (or DC voltmeter appropriate file) file, black, red table pen, respectively, "Grid" and the generator "electricity "Pivot" the column, turn the belt pulley by hand, the multimeter (or DC voltmeter) pointer should swing, otherwise the generator does not generate electricity.