Electric Motor

by: muhammad suhandi

Electric Motor is a device that converts electrical energy to mechanical energy. Principally there are two types of electric motor, DC motor and AC motor. AC motor is sometime named induction motor. It is used to make distinction between synchronous motor and asynchronous motor. All types of electrical motor have the same main construction. It is formed by two main parts. The rotor that rotates and stator that always in stationer.

Other terms we usually encountered in electrical motor is armature and field. Armature is the component that housing the winding or the conductor, which the electrical power comes. Field is winding provides the magnetic field to as an important factor to convert electrical energy into mechanical energy.

Every electrical motor has its armature and field. Now we explain the DC motor. DC motor is the motor supplied by DC voltage and current source. Its armature is in the rotor and the field in it’s a stator. DC motor usually used in industry because its rotation is easy to manipulate. But because our utility supplied AC sources, the need for a rectifier is rised. So it is rather expensive if we use this type of motor for large application. Now the DC motor is dominant in low power spectrum.

Because the nature of our utility industry is AC, the need for motor that supplied by this type of sources is rised. First is syncronous motor. This type of motor actually same as generator but work in reverse direction. Its contruction is all the same as generator. This motor has limited application because its dificulty to handle its speed. Syncronous motor is mainly used as synchronous capacitor.

In early twentieth century, Tesla an electrical engineer came with idea to design the motor that supplied by AC sources. Its construction is actually same as a transformer except it has an air gap to make it rotates. The induction motor has two types that depend on its rotor construction, squirrel-cage rotor and wound rotor. The analysis of induction motor is the same for transformer except we should introduce the speed parameter.

Induction motor is mainly used to drive large load in industry. These motors supplied by three phase AC source. For home appliances because our utility outlet is single phase in nature we used single phase induction motor.

The isueses of global warming, increase oil price has force the engineers to install electrical motors in our cars. The type of motor could be DC or even induction motor. There is hybrid car that moved by two sources, the internal combustion engine and electrical motor supplied by batteries. For pure electrical cars, no engine installed. All wheels moved by electrical motor supplied by batteries that could be charged from our utility outlet. That is the future.