Alternator Problems

In many cases, soon after a new alternator has been installed, it is found to have failed prematurely. We will try to highlight some of the probable causes of premature failure. We have included illustrations of some common problems.

Because many of the new alternators are capable of charging at rates in excess of 110 Amps, the battery should be fully charged before use to avoid overheating the alternator by trying to use it as a battery charger. Alternators are NOT battery chargers, they are battery maintainers as well as supplying current for vehicle amenities. Symptoms of this type of damage are a burnt stator.

In many newer vehicles, the alternator is located in an area that allows very little ventilation. The area around the rectifier on the back of the alternator plugs up with dirt and fibers, causing the unit to overheat.

Rear alternator bearing failure may be caused by over tightening the belt or a seized belt tensioner. The bearing is retained in the alternator by either an aluminum ring or a plastic retainer, which under pressure, will collapse.

Drive belt slippage may cause overheating and bearing damage.

Thread damage on the rotor of the alternator is caused by improper pulley installation methods.

Cracked terminal insulators are cuased by over tightening the terminal nuts.

Improper changing of the alternator clock postion may result in broken brushes and brush holders.

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