Car is a system, operation of which depends on many small components. That’s why, in case of failure even of smallest part, whole vehicle will malfunction. Alternator is one of such components.
This pack provides current flow for all vehicle devices and systems, which are elements in complex circuit of electric accessories. Also alternator is responsible for battery recharge, while use. Despite of vehicle move, the alternator must provide optimized charge for battery. Besides, battery is very sensitive to electric charge and because of that the work of alternator must be flawless.
1. What you should know for diagnosis and repair
2. Alternator failures and repair
• Strange noises
• Control panel light blinks despite of charging
• Alternator provides no charge
If work of alternator is incorrect or unstable, then car battery will recharge awfully bad. Without alternator operational all load will fall on car battery, which won’t last long under it. In other words, the battery will run out fast. And if it happens, the engine will stall out. And this can occur at the most inappropriate moment and place. To avoid such troubles you must look after this component of your car.
1. What you should know for diagnosis and repair
Before running a diagnostics, you should remember several precautions. It is not allowed to:
Check alternator operation through short-circuit;
Turn off the alternator without consumers or while battery is on;
Weld parts of car body if wires of battery and alternator are linked.
Except precautions, there are also significant indications related to alternator repair and inspection. The work of alternator can be inspected only with amperemeter or voltage meter. While performing alternator vents diagnostics, the voltage must be 12V or higher.
Before checking alternator you must make sure that all joints are operational and alternator belt is adjusted correctly. If you notice that alternator wires must be replaced, then new wires must be of the same length and have the same sections as old ones.
There is an indicator on control panel, which signalizes that battery ran out. There is also a voltage meter. So, if the light is on and the arrow “went far”, then there is time to look under hood.
The diagnosis must be started from alternator belt inspection. You can check it by turning an alternator pulley. If the pulley slips, then it needs adjustment. But if the belt is just strained, then it must be replaced with a new one.
The belt must be tensioned by moving the alternator along suspended riffle, while the retaining nut eased off. If the drive gear is intact, then you should continue inspecting the alternator to find worn out component. It is forbidden to remove accumulator terminals to check alternator operation, while engine is on.
This action may cause alternator breakdown because of electrical power surge. It must be connected to battery terminals. Start engine first. At the moment of starting the index of strain on pulleys must be 8V or higher. Then increase engine rotational rate to 3000 rpm. In this case index of strain must be 12.5V or higher. If the index is lower, then you must repair the alternator.
As vehicles are used for quite long period of time, a list of typical alternator failures already exists. According to experts, the most widespread breakdowns are following:
Strange noises that occur during alternator operation;
Insufficient strain provided by alternator;
Vehicle power failure.
Before starting repair of alternator, it must be dissembled. You’ll need to:
- remove brush arm and voltage adjuster;
- remove all fixture element;
- remove draft bolts and disconnect phase winding from power unit;
- remove starter cover assembly;
- remove shaft pulley;
- remove front cover.
2. Alternator failures and their repair
Pay special attention to rotor bearings. If they are damaged, you must replace them immediately or the consequences will be bad. If their endfloat is in order, then you just remove the bearings, wash them in petrol and cover them with oil filling before installation. After all these preparations, install the bearings back.
Provided strain is insufficient for normal system functionality. The problem is might be in battery relay switch, which must be replaced. Sometimes failures are caused by diodes of diode bridge. They must be replaced, if they are faulty.
Control panel light blinks despite of charging
Most often, in this case, it is abruption of diode responsible for normal operation of supply circuit connected to this indicator. The diode is located on diode bridge. To repair this breakdown, you must replace diode bridge. To do so, remove fixtures of stator winding.
Alternator provides no charge
Problems connected to this case may be different: safety appliances malfunction, voltage control group relay defects, problems with brushes (worn out, stick or broke down), stator chain abruption, closing in windings.
First three alternator breakdowns are repaired by replacement of necessary component. All other problems can be solved by manual repair. Closing and abruptions may occur right at slip rings. To repair this defect, unwind one turn of winding in order to solder it to the ring. Remove broken wire and solder new one instead (you will get it after unwinding).
The most widespread alternator failure may be caused by bearings wear out or malfunction. Sometimes alternator can make noise that you won’t hear the engine.
To make sure that this noise comes from alternator, just press the accelerator. After that the noise will become louder due to direct connection of alternator with engine. In other words, alternator spring-back depends of engine rotation. The more rpm, the louder is noise. That means that alternator bearing diagnostics lies in noise listening during its operation process.
It is quite easy to perform an alternator repair. In most cases you can do it on your own. Good luck!