Comparison of D.C generator or alternator?


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abhi khan answered
The AC generator or an alternator is a device which generates alternating current by converting an engine's mechanical energy (turning energy) into an alternating electrical current at all engine speeds. The AC must be rectified or converted from AC to DC prior to reaching the vehicle's electrical system. The alternator operates by a belt at the front of the engine. This unit transforms the 12-volt DC (Direct Current) from the battery into AC (Alternating Current) at the rate of 13.8 to 14.2 volts, which is required for your car's performance and also for the working of your electrical systems.

The nature of the AC current is such that it is produced at a higher rate and is considered to be more stable. The main difference between a dc generator and an alternator is in the way the rotating coil is attached to the external circuit containing the load. In an ac generator, both ends of the coil are linked to separate slip-rings which rotate with the coil. In a DC generator, two ends of the coil are connected to separate halves of a single split-ring, which rotates along with the coil.

THe Alternators are used in automobiles to charge the battery and to power all the car's electric systems when its engine is running. Alternators have the great advantage over direct-current generators of not using a commutator, which makes them simpler, lighter, and more rugged than a DC generator. The stronger construction of alternators allows them to turn at higher speed, allowing an automotive alternator to turn at twice engine speed, improving output when the engine is idling. The availability of low-cost solid-state diodes from about 1960 allowed auto manufacturers to substitute alternators for DC generators. Automotive alternators use a set of rectifiers (diode bridge) to convert AC to DC. To provide direct current with low ripple, automotive alternators have a three-phase winding...hope that helps :d

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