What are Permanent Magnet Alternators?

A Permanent Magnet Alternator is an electric generator which is used to convert mechanical energy to AC electrical energy. The use of permanent magnet in place of field coil is a distinct new process which has grown in popularity over the years. High-quality permanent magnet alternators are increasingly being deployed in modern technological applications including commercial and industrial electrical energy generation, flywheel storage systems, air-conditioning and heating, travelling wave tubes as well as electric motors in hybrid cars.

How Does a Permanent Magnet Alternator Work?

A permanent magnet alternator does not require a DC supply for excitation circuit, nor does it need to have slip rings or contact brushes. Permanent magnets are embedded in the steel rotors creating a constant magnetic field. The stator carried windings are connected to an AC supply to produce a rotating magnetic field. At a synchronous speed, the rotor poles lock to the rotating magnetic field. The rotor and the magnetic field rotate with the same speed because the magnetic field is generated through a shaft-mounted permanent magnet mechanism while the current is induced into the fixed frame.

There are two kinds of assemblies of permanent magnet alternators: one with an internal rotor and external stator and the other with internal stator and external rotor. The permanent magnet alternators with external stator give better performance in terms of power-to-weight and torque-to-weight features.

The constant flow of current results in the machine heating up, and that is why the cooling process is essential to an alternator’s efficiency. In order to aid in heat dissipation, most alternators have vents on both the front and side while some modern alternators have cooling fans inside them which operate the same way, using mechanical power from the rotating blade shaft.

Why Do You Need Permanent Magnet Alternators?

Steam, gas, hydro and some types of wind turbines use permanent magnet alternators because of their inherent simplicity, dependability and consistent performance. PMAs are also used in cars, motorbikes, aircraft engines as well as home appliances such as lawn mowers and chain saws. A permanent magnet alternator is also light-weight, portable and less space-consuming, which is why they represent a very viable alternative to conventional generators.

Furthermore, unlike generators which consume all the energy that is produced, alternators use only the minimum amount of energy, conserving more power and helping you save on your electricity bills. A permanent magnet alternator also creates continuous power irrespective of the power demand and therefore it has a better load management than conventional generators.