An alternator in a car can be compared to a bicycle alternator: the faster the alternator rotates, the higher the voltage rises and, consequently, the supplied current increases. The current consumers in the car would not withstand such a rise and fall of voltage for a long time, so a special regulator must limit the voltage of the generator and prevent overcharging of the battery. This regulator, an electronic excitation circuit regulator, is bolted to the outside of the Bosch generator. In the Delco Remy generator, the regulator is located inside the case.
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