Electric motors use a combination of magnets and electrical current to convert energy into mechanical energy. They can be found in many applications, including industrial fans and blowers, machines tools, power tools, household appliances, disk drives, and vehicles.
A motor has two mechanical and electrical components – a fixed stator and a rotor that turns to generate mechanical output. These components are set up so that a magnetic field produced by an electrical current in the windings of the stator creates a force between the armature and the rotor.
The armature contains wound wire on a ferromagnetic core of iron. When current flows through the windings, the magnetic field exerts a Lorentz force on them which rotates the rotor.
There are many types of electric motors based on how they are constructed. These can include non-salient, round-rotor, distributed field, shaded-pole, and permanent magnet synchronous motors.
In the case of permanent magnet synchronous motors, a regenerative brake (or generator) may also be used. This is to recover energy that could otherwise be lost as friction and heat.
Three-phase AC induction motors are also a popular option for EVs, as they can operate from the battery or a direct-current (DC) source. These are usually brushless, which means they do not require brushes for commutation or conversion to electricity.
They can run at high speeds and produce a very low power factor. This is because they generate a rotating magnetic field that makes the rotor spin at an angular velocity which matches that of the load.
Some motors are also doubly fed, which means that they have two active winding sets, each of which contributes active power to the energy conversion process. Doubly-fed electric motors can produce twice as much torque as singly-fed motors with one active winding set.
When the windings in a motor become too hot, they can melt, and this can damage the motor. To prevent this, the wires should be rated for a maximum operating temperature, or they can be protected by insulation.
The most common type of electric motor is the DC motor. These are the most common for small motors, such as those in electrical watches and computer printers.
A DC motor has a rotor and a stator. The stator is a metal plate that surrounds the rotor and holds magnets. These are either electromagnets, which are made from wound wire on a ferromagnetic iron core or permanent magnets.
An electromagnetic core consists of a series of iron laminations which have been covered with an insulation that is similar to steel. The insulation is a thin layer which reduces energy loss and dampens vibration.
These types of motor are typically used in applications where they must be able to operate at high temperatures and for long periods without burning out. For example, they are frequently used in motors used to power boat propellers and industrial cooling fans.
Induction motors are an alternative to the DC motor and they are a good choice for applications where they will be used at high speeds and with high loads. They can also be made to run on a DC supply, which can make them cheaper than their synchronous counterparts.