Common faults and maintenance methods of car generators
1. No charging
When the engine is at a medium or higher speed, The pointer of the ammeter indicates no charging, and the charging indicator light is on. First, consider the charging condition of the battery. If the charging is insufficient, the generator is faulty.
No charging In addition to the fact that the drive belt is too loose and slipping, it is generally necessary to check that the generator itself does not generate electricity or the regulator is faulty, and the charging circuit is open circuit fault. For example, the internal rectification of the generator falls off or the bottom of the armature terminal is not in contact with the diode element board; the diode breaks down and short-circuits, causing the stator winding to burn out; the brush is stuck in the carbon brush holder and has poor contact, or the magnetic field winding is open circuited, etc.
In the diagnosis, increase the engine speed; turn on the headlights, if the pointer of the ammeter deflects the discharge direction instantaneously, it means that the generator and the regulator are working normally, but the battery is fully charged; if the pointer of the ammeter deflects In the discharge direction, the fault lies in the generator or the regulator. Check whether the connectors of the charging line are in good condition, whether the fan belt is too loose and the technical condition of the generator and the regulator. First, verify whether the charging system is indeed faulty, set the engine to run at a medium speed, and at the moment when the headlights are turned on, the pointer of the ammeter deflects to the “+” direction or remains in place, indicating that the battery is fully charged and the charging system is working normally. If the pointer of the ammeter deviates to the “one” direction, the charging system is faulty and should be repaired.
2. The charging current is too small
In the case of insufficient battery storage, increase the engine speed, and the ammeter pointer will indicate If the charging current is smaller, the charging current is too small fault. This is generally caused by insufficient voltage of the generator itself, poor technical state of the regulator and increased resistance in the charging line.
The following steps can be used to judge and eliminate: Check whether the terminals and wires of the battery, generator, regulator and ammeter are connected securely. Check whether the fan belt is too loose and the generator speed is not high. When the above conditions are normal, the limit voltage of the regulator can be checked at the medium speed of the engine, and the generator can be disassembled to check whether there is any abnormal phenomenon of wear and damage. Check whether the movable contact of the adjuster is ablated or whether there is oxide, whether the gap between the movable contact arm and the iron core and whether the spring tension meets the technical requirements; whether the connection of the adjuster is loose. Any abnormal phenomenon should be repaired in time. When the engine is running at a medium speed or above, turn on the headlights. If the current still shows charging, the charging system is in good technical condition; if the power meter shows discharge, the charging current is too small, and it should be repaired.
3. Excessive charging current
The pointer of the car ammeter deflects to the maximum charging current position. If you drive at night, when the engine speed is high, the lighting and instrument indicators will be particularly bright, resulting in easy burnout of bulbs, ablation of distributor contacts, and excessive consumption of battery electrolyte.
First, check whether the live wire and the magnetic field of the regulator are connected incorrectly, and whether the movable contact is ablated or glued to the normally closed state. When checking the regulator, the magnetic field wiring can be removed. If the charging current is significantly reduced, the regulator is faulty. It may be that the low-speed contacts cannot be sintered apart, and the coil has an open circuit. If the charging current is still large, it may be the magnetic field wiring and There is a short circuit in the armature wiring. First, check whether the charging current is too large due to the internal short circuit and serious power loss of the battery and should be repaired.
4. The charging current is unstable
When the engine is running above the idle speed, the pointer of the ammeter swings left and right, indicating intermittent charging (sometimes charging and sometimes not charging) phenomenon), generally the terminal voltage of the generator is unstable.
First of all, check whether the connecting wires are loose and have poor contact, whether the belt is too loose and whether the poles of the battery are loose. If there is no abnormality, then check whether the contacts of the regulator are ablated, dirty, whether the coil or resistance has poor contact, open circuit, etc. If there is still no abnormality, the internal technical condition of the generator should be dismantled and repaired one by one. When the generator is running above the medium speed, the ammeter indicates charging, but the pointer keeps swinging left and right, and the charging current is large and small, which should be repaired.
5. The generator does not generate electricity
The main reasons for the generator not generating electricity are: rectifier diode breakdown short circuit or open circuit; excitation winding short circuit or open circuit; The three-phase stator winding is short-circuited or grounded; the rotor slip ring is seriously oxidized and dirty, the carbon brush holder is damaged or the carbon brush is stuck in the brush holder. Step by step to investigate the cause and repair it.
Precautions for maintenance of automobile generators
1. The connecting bolts (females) of each part of the generator should be tightened and reliable, and the wires should be in good contact to avoid loosening and falling off. affecting work.
2. The positive diode of the generator is press-mounted on the component board, and the negative diode is press-mounted on the generator shell, and the two must not be mounted wrongly. When pressing the diode, its tightness should be appropriate. Too tight will easily damage the diode, and too loose will cause flashover.
3. Strictly keep the negative pole grounded when installing and replacing the battery. The polarity of the generator must not be reversed, so as to prevent the diode from burning out. During the maintenance, the test fire method, short-circuit method and megohmmeter shall not be used to check to prevent the diode from being damaged.
4. Each line column is not allowed to be loose to prevent the diode from being damaged by poor contact or instantaneous overvoltage.
5. The generator should be regularly maintained according to the technical specifications, and the failure should be repaired and eliminated in time.
6. Keep the wiring of the generator and the regulator in good condition, and the installation is firm, and the negative grounding iron must not be mistaken.
7. Use the correct operation method to overhaul its faults to avoid man-made mechanical damage.
Declare: The above methods are derived from the program system index or shared by netizens. They are for your reference only and do not represent the research views of this website. sex and authority.
