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Alternator Repair

Here are some troubleshooting tips on fixing alternator problems.
Omkar Phatak
Alternators are called so because they are alternating current generators. Based on the principle of magnetic induction, these devices use the torque provided by car engines, to generate electricity. The alternating current generated, is converted to a direct current and is used to charge the car battery.
All the internal systems are provided power through the car battery, which is constantly replenished with charge, as your car moves. An alternator consists of magnets, rotors, and a rectifier mechanism. Its belt transfers torque from the engine, to drive it.


The simplest way of checking alternator health is through observation of the pilot light, provided on the car dashboard. If it's off, you must get the device checked. Low battery voltage and overall diminished performance of electrical accessories is another indicator of a bad alternator.

Repair Overview

There are specialized repair kits available to those who need to fix it on the go, when replacements are not available. Here are some repair jobs that you may need to carry out.

Replacing the Belt

One of the most common repair tasks is replacing a worn out belt. If it's frayed and worn out, with loss in tension, it is best that you get it replaced.

Replacing Rectifiers, Regulators, and Brushes

Check the car battery and make sure that the problem lies with the alternator itself. If its belt is also in top working condition, then the problem lies in the interior of the device. Most problems arise because of a failure in the internal rectifier bridge or diode, that may have stopped working.
So, the repair in this case, involves the complete dissection of the device and replacing of dysfunctional parts. You will have to remove the alternator from the entire assembly and take it apart, piece by piece. You need to remove the rectifier and diode assembly from the aluminum casing and also clean out the rotor.
Using a repair kit and the instruction manual provided with it, you can test and replace the faulty rectifier bridge, diodes, and regulator. Check if the internal magnets are still functional. If they are not, there is no point in repairing an alternator. The only option is to replace it.

Replacing the Alternator

In case, it is beyond repair, replacement is inevitable. Refer to this guide for detailed information about how to go about it.
Doing the whole repair job on your own will lessen the repair cost, but if you are not confident enough, hand over the job to a professional. When it comes to car parts like alternators, it is best to replace them altogether, if there is an anomaly in functionality.
The cost of replacement is quite low. So, you don't have to think twice before getting it replaced. If it has ended its service life, there is no point in going for repair, as you can't take chances with this device.