Knowing what components are in an alternator, and what they do to make an alternator operate properly, will help to determine if a malfunctioning charging system is caused by a faulty alternator or some other component in the charging system. This information will also help you to decide whether the “mechanic” working on your car is telling you the truth about what is wrong with your charging system, or whether he is trying to get you to approve unnecessary repairs.
The components of the alternator are the two piece cast aluminum housings, rotor, stator, pulley, cooling fan, rectifier bridge, slip rings, alternator brushes, and, on some applications, an internal voltage regulator. The alternator housing encapsulates the rotor, stator, rectifier bridge, and, in some alternators, the cooling fan and internal voltage regulator. The pulley end or front half housing has a through hole or bore in the center of the face of the housing to accommodate the front alternator bearing, which is usually press fit into the hole. The rectifier end or rear half housing also has a bore in the center of the inside face of the housing. The bore allows for installing a brass bushing or roller bearing which, like the front bearing, are usually press fit into the bore. The bearings and/or bushing support the rotor shaft ends and allow for easy shaft rotation. Both housings are ventilated by means of slots and holes to help keep the alternator cool during operation. Both housing halves are held together by long through bolts. Some alternators require that the housing halves be mounted together in exactly the same orientation in order for the alternator to operate properly. Other alternators allow for the housing halves to be rotated in order to facilitate proper mounting to the engine. The housings are cast aluminum because they are nonmagnetic, lightweight, and very efficient in heat dissipation. If the housings were cast iron the magnetic field created by the alternator could be so intense and strong that electromagnetic interference, EMI, could adversely affect other electrical devices on the engine or in the engine compartment.
The next article will continue discussing alternator components.
As always, if any procedure in this series of articles appears to be beyond the capabilities of the vehicle owner or driver, then testing and servicing the alternator should be performed by a professional or ASE Master Certified mechanic. The vehicle would have to be taken to a repair shop that employs these types of mechanics such as A & M Alternator Services located at 2419 E. Jackson St. in Phoenix, Auto Electric Specialists located at 5216 W. Lamar Rd. in Glendale, Village Auto Electric Service located at 19 N. Miller St. in Mesa, All Start Electric located at 13501 E. Chandler Blvd. in Chandler, Jordan’s Automotive Specialists located at 8718 E. McDowell Rd. #3 in Scottsdale, Rob’s Quality Automotive located at 11801 N. Cave Creek Rd. in Phoenix, Scottsdale Pro Tech located at 8245 E. Butheruand Dr. #111 in Scottsdale, and Art’s Family Auto Repair located at 915 W. Hatcher Rd. in Phoenix.