We all expect our car to start every time we turn the key. And it usually will, as long as there’s enough electricity stored in the battery to do the job. That’s especially important when the temperature outside is unusually high or unusually low, when demands on the starting system are at their highest.
indeed for all this to happen there is need for a alternator that continuously charges the battery.Alternators are used in modern automobiles to charge the battery and to power the electrical system when its engine is running.
An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature. Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used.
A car’s charging system includes an alternator (which is an AC generator), a voltage regulator, necessary wiring and, of course, the battery itself. The alternator, about the size of a small coffee can, is mounted to the front of the engine and is driven by one of the engine’s belts. So it only operates when the engine is running.
Cars operate on DC electricity, so the charging system requires a component called a rectifier to change the AC output to DC.
Alternators do a terrific job of producing electricity, but require some sort of device to control just how much of the voltage is allowed to reach the car’s electrical system to meet operating needs. This same device must also control how much electricity gets put back into the battery. This is the job of the voltage regulator.
The voltage regulator operates much like a faucet, opening and closing (electrically, of course) as needed.
Voltage regulators monitor the needs of the car’s electrical system, and also the level of charge in the battery, and adjust the alternator’s output accordingly
Unfortunately, alternators don’t usually give any warning that they are about to fail, not from the headlights dimming or from dim interior lights. Perhaps the only symptom is a battery that seems weak when you try to start the engine. Of course, that could simply be a weak battery that is unable to fully charge.
To let the driver know his charging system is operating properly, vehicles are equipped with a system warning light or voltmeter gauge on the dashboard. A voltmeter shows total system voltage at a given time. The warning light simply comes on to show there’s some sort of malfunction in the charging system.
When your warning light or gauge indicates a failure in the charging system, it’s time for a professional technician to perform a diagnosis. With the proper equipment a technician can not only check the charging system, but can do a load test on the battery to see how healthy it is.