Alternators and How They Work

We all know that we have an Alternator in our car; but do we know what it does? I don’t, and if you don’t know then that’s why you’re reading this article; right? Well let me get to explaining.

An Alternator is known as an electromechanical device that transforms mechanical energy to electrical energy; it does this in the form of alternating current. The most common Alternator usually uses something like a rotating magnetic field, but linear alternators are used occasionally. If you want to be pretty general, any AC electrical generator can be referred to as an Alternator - but technically, the word is usually used to refer to small rotating machines driven by cars and some other internal combustion engines. The Alternator that’s in power stations driven by the steam turbines are called turbo-alternators.

The basic Alternator is designed to generate electricity by the same principles as the DC generators generate energy. Ordinarily, the rotor (a rotating magnet) turns within an immobile set of conductors wound in coils usually on an iron core; this is called the stator. The field is supposed to cut across the conductors, which generates an induced EMF, as the mechanical input is the thing that causes the rotor to turn.

The rotating magnetic field usually produces an AC voltage in the stator windings. There are frequently three different sets of stator windings; they are physically offset so that way, the rotating magnetic field can produce three phase currents. They are displaced by 1/3 of a period with respect to each other.

The rotor magnetic field can be produced by three things: Induction, Permanent Magnets, or by a rotor winding energized with direct current through different slip rings and different brushes. The Induction is in a “brushless” Alternator and the Permanent Magnets are in really small machines. Sometimes, the rotor magnetic field can even be provided by stationary field winding; this means there has to be moving poles in the rotor. The Automotive Alternator always use a rotor winding. Since the typical permanent magnet field is constant, the terminal voltage can varies straight with the speed of the generator. The Brushless AC generators are almost all the time bigger machines compared to the ones that are used in automotive applications.

The Alternator that’s in your car is usually there to charge the car’s battery and to give power to the electric system while your car’s running. The stronger your Alternator is, the less pulley so as to turn faster than the Rebuilt Auto Engine - this can typically improve output when your engine is idling.

The Alternator that’s found in your usual passenger and light trucks use either Lundell or claw-pole field construction. This is where the field north and south poles are all energized by one single winding - the poles look more like fingers of two hands that are interlocked with each other. The bigger vehicles can typically have a salient-pole Alternator that are similar to what the bigger machines use. The Alternator in cars is almost all the time belt driven at 2-3 times the engine crankshaft speed. The Automotive Alternator is not really restricted to a specific RPM because the alternating current is rectified to direct current and there doesn’t have to be any constant frequency.