An alternator is part of the electrical charging system for your Ford or Holden vehicle.

What does it do?

It’s a compact generator of electricity for many of your vehicles electrical devices. A type of on-board power station, the alternator transforms mechanical energy from the engine into electrical energy. Although your vehicle battery supplies some electricity most of the electrical mechanisms within your vehicle require the alternator's steady stream of power to keep them operational.

Alternating current (rather than direct current) gives the alternator its name, because this is the type of electricity it produces. The alternator is a mechanical as well as an electrical device, consisting of a pulley, wheels, brushes and wires, which is then driven through the pulley system to the crankshaft of the vehicle engine and is connected to the battery. The alternator converts that continuing engine motion into an electrical current whenever the vehicle is running. The resulting electricity operates a number of devises including the engine cooling fan, headlights, taillights, windshield wipers, audio system, power steering, electric windows and of course the air conditioning. Your vehicle alternator is very efficient at producing constant high voltage alternating electricity even when your vehicle is idling.

How does it really work?

There is a belt from the crankshaft of the engine that connects to a pulley system. It's called the rotor so that when the belt is turning it moves magnets across a conductor. The moving magnets in the alternator then generate the electricity for your vehicle. A voltage regulator is there to keep the voltage steady and controls this alternating current. Other parts, called the diodes, convert the alternating current into the direct current that flows on to the battery and any other electrical components.

What can go wrong?

Even if your alternator fails or malfunctions, your Ford & Holden vehicle can still keep running for a while. It will run directly off the stored power in your vehicle battery, that is until all the battery's power is used up. Therefore, it is hard to tell when your alternator has a problem or has failed. You could hear a harsh noise, or have headlights that are intermittent. Check to make sure the belts on the alternator are not cracked, damaged or improperly tightened. The alternator is one part that is difficult to see if it’s failing.

What can you do?

If you are looking to replace or need some advice about a defective alternator then you should talk to one of our Ford & Holden parts experts. If you find it necessary to replace your alternator it is almost always best to send the old unit back to our parts store as the core from your old alternator can repaired and sold as a rebuilt unit. These will cost only a fraction of the price of a new alternator and we think this is a great solution. Our rebuilt alternators come with New Zealand’s best second hand part warranty.