An alternator is part of the charging system of your car that produces electricity for many devices. A type of generatorit transforms mechanical energy into electrical energy. Although a car's battery supplies some electricitymost of the electrical mechanisms within the vehicle require the this device's steady stream of power.
Alternating current (rather than direct current) gives the alternator its namebecause this is the type of electricity it creates. It's mainly a mechanical deviceconcealing a pulleywheelsbrushes and wireswhich hooks to the crankshaft and runs to the battery. This waythe gasoline powers the engine to turn the crankshaftwhich in turn connects to the alternatorwhich converts that motion into current whenever the car is running. The resulting electricity operates the cooling fanheadlightswindshield wipersradiodefoggerand air conditioning.
To be more specificthis part is very efficient at producing a constanthigh voltageeven when the car is idlebecause of how it works. The belt (from the crankshaft) connects to a pulley systemcalled the rotorso that when the belt is turningit moves magnets across a special surfacecalled a conductor. Moving magnets in the stator generate an electrostatic fieldotherwise known as electricity. This alternating current is controlled by a voltage regulator to keep the voltage steady. Another partcalled the diodesconvert alternating current into direct current that flows on to the battery and other components.
Even if an alternator dies or malfunctionsthe car will run for a while directly off of the battery until all of its power is sapped. This makes it hard to tell when the device is having problems. Sometimesa harsh noise or intermittent headlights will give it away. Drivers should check to make sure the belts are not crackedor improperly tightenedbefore replacing the entire part. A rebuilt alternator can be a reliablebut less expensiveoption if it must be repaired.
