How to rebuild an Alternator

The Alternator is a quite complex piece of electronics. It is the new age generator in cars which has in recent years replaced dynamos which used to provide electrical power to the car. The idea is too convert mechanical (kinetic) energy into electrical energy, in order to power the cars electrical components as well as recharging the batteries. The basic principle relies on research by Michael Faraday back in 1831 when he noticed what we now know as electromagnetic induction. As a battery moves within a coil of wire a current and voltage is induced within the wire.

Faradays discovery: Electromagnetic induction (1831)

In a car the magnet spins with the axle, this provides the movement, and since the amount of curent depends upon the stregth of the magnet and the speed at which it moves, this provides a fair amount of power. The stator acts as a coil, and takes an enduced alternating current when the magnet spins within it.

When alternators fail the electrical components in a car all suffer so there are a range of symptoms which you can spot, like; misfiring, cutting out power, computer failure and devices such as tachometers will no longer work.Buying a new alternator can be very expensive.. SO

HOW DO YOU REBUILD IT?

Unfortunately, for a lot of people this will be very difficult, it is quite a complicated process and requires some knowledge of electronics as well as mechanical systems. Another bad thing: most handbooks and car guides will not tell you how to rebuild your alternator, and they are not standard so you will have to use your head a lot and your initiative whilst trying this.

make sure you disconnect the battery before you begin!

Labelled diagram of alternator

1. Make sure you have good access to the connections and mounting bolts before you begin, on different cars this may mean removing some other components. Now, locate and remove the electrical leads to the alternator, mark them and try to draw a diagram so you do not forget where you took them from.

2. Remove the Alternator bolts, again mark and draw were they came from so you dont loose or put them back in the wrong place, then remove the alternator from the car.

3. Remove the plastic covers on the alternators (if there are any) now take a good look at where all the wires are and what they link together and write it down before you remove anything! i cant stress this enough, the worst thing that can happen is you take it apart and loose a piece or forget how it all went back together!

RECTIFIER

4. Now we can start with the rectifier, this can be removed by pulling off the soldered leads, and unscrewing the mounting screws

5. Get your new rectifier and replace it in exactly the same spot, making sure you replace all the screws and wires into the correct ports. You will have to re-solder the wires back to the terminals.

BRUSHES

6. Now we need to replace the brushes, undo each of the holding screws and slide them out of their channel. clean the contact area of each brush on the armature shaft. Slide on the new brushes making sure the spring is exactly on the back of the brush such that it fits exactly into the slot.

VOLTAGE REGULATOR

7. remove the screw of the bottom brush and the grounding screw. Switch the old and new units and replace all the screws and covers removed in the last few steps.

8. Re-apply the alternator to the car in the same way you removed it in step 2, reconnect all of the leads using your previously drawn diagram as reference. Replace all components removed to get to the alternator, check all of its components are correct (belt tension, heat shield etc..) before reconnecting the battery!

SORTED

Alternator in place

hopefully this Will help you, it should apply to a wide range of alternators, but many vary so consulting a book about the differences would be a good idea!