Some of the more commonly-known alternator parts are the brushes, stators, bearings and pulleys. Many of the alternator parts such as the housing, cooling fan and the wiring harness are overlooked when any discussion about the alternator takes place. These are, however, very critical alternator parts that are directly responsible for proper operation of the component. While replacement of the entire assembly is often practiced to cure alternator problems, the alternator parts are often easily exchanged, making rebuilding the alternator a viable option in most instances.
The main component in an alternator is wire. Of all of the alternator parts, the wire is the key to producing electrical power. One of the most crucial components of all the alternator parts, however, is the cooling fan. Heat is the enemy of any alternator, and the inclusion of a quality cooling system is crucial to the long life and proper operation of the charging system. Many times, the importance of the cooling fan is overlooked when discussing critical alternator parts.
Most manufacturers use one of two types of fan designs. The simple stamped metal fan is the most common, with the other being similar in design to the impeller found inside many water pumps. The drive pulley is also a major factor in the operational success of an alternator. The speed at which an alternator is driven is directly related to the size of the drive pulley on the component. Changing the speed at which the alternator is turned directly affects the rate of charge the unit produces as well as the rate of cooling the fan allows.
A primary cause of most alternator failures is the brushes. The brushes are the point of contact between the spinning stator assembly and the stationary rectifier. This is also the gateway for the electricity produced by the alternator parts and the charging system. In many instances, replacing the brushes alone will rectify most alternator troubles. Advancements in bearing design have eliminated the bearing problems that would often be the cause of many alternator noise issues and failures.
Most alternators used since 1973 have included an internal voltage regulator. Prior to this, the regulator was mounted on the vehicle's firewall or radiator support and was the source of many charging difficulties. The inclusion of this component with the alternator parts has reduced the troubles commonly associated with the older charging systems. Fortunately, this newer-style alternator is easily retrofitted into older charging systems.