# Electric Motors

### Brushless DC Motor

When we refer to an electric motor, we are talking about a device that is capable of converting electrical energy into a driving force; in the case of these motors, it is a rotary-motor force and a linear motor force.

Here, I will briefly explain the electric motor definition, the main parts of a motor (construction of motor), and the electric motor’s working principle.

The electric motor is one of the most important inventions of modern times. We rely on it continuously in all things, ranging from movement in the wristwatch to the spacecraft’s movement.

The electric motor’s definition is that ” it is a device that converts electrical energy to the movement (mechanical energy)” … to go on deep on how this electrical energy is converted to mechanical. We will find the answer to this question with the inventor Faraday.

So, let us explain:

How does electrical motor work?

Or

what is the working principle of the electrical motor?

Or

How does an electric motor working physics?

The motor’s idea depends on Faraday’s law … Faraday’s  Law states that the induced electromotive force or EMF in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit.

(motion – field- current)

While we have current and field in the motor, so we can easily take a motion from the motor. Also, we can control the movement speed by controlling the current and field.

The second thing is the types of electric motor … so we must ask ourselves an important question :

what are the different types of the electrical motor?

Before we talk about the motor’s construction, we will talk briefly about the types of motor due to the different internal structures of each type of motor.
1. AC motor: Alternating current motor
It may be a single-phase motor or three-phase motor according to its application … and this motor has types such as:

a. synchronous motor.
b-Induction motor.
c-Special motor.
d-Linear motor.

I will explain every type of AC motor in full detail.
2. DC motor: Direct Current motor
These types of motors are fed from DC source … and these motors have these types:

Series motor.
Shunt motor.
Compound motor.
Permanent magnet.
Universal motor.
Servo motor.
Separately excited DC motor.

Each will be explained in subsequent articles.

The third thing you must know about the electric motor is the parts of a motor:

Below you will find all parts of any motor … it is general for all types:

Enclosure (AC & DC motors)
Stator (AC & DC motors)
Rotor (AC & DC motors)
Bearings (for AC motors only).
Commutator (for DC motors only).
Brushes (for DC motors only).
Conduit box (AC & DC motors)
Eye Bolt (AC & DC motors)

This is the basic structure of all motors, but minor differences are depending on the motor type.
Parts of a motor
1. Enclosure:
The first and main objective of this is to protect the internal parts of the motor. Therefore, its types vary according to the work environment.
It should be noted that the difference of its type affects the cooling method.

Here are some of these types.

a. Type;

Open Drip Proof (ODP)

Used in;

Indoor application
In clean and dry environments

Function;

Prevent drops of liquid from entering the motor within a 15-degree angle from vertical

b. Type;

Totally Enclosed washdown (TEWD)

Used in;

Chemical environment
Not recommended in hazardous environments

Function;

Withstand high-pressure washdown

c. Type;

Explosion-proof enclosures(EXPL)

Used in;

In hazardous environments

Function;

Withstand The explosion of gas and steam inside the engine and prevent ignition outside.

2. Stator:
It is the fixed part of the motor, and the coils are wrapped around it.

The stator may be windings or permanent magnets slices of the metal sheet called laminations isolated from each other by varnish to reduce energy loss and heat.
3. Rotor:
It is the moving part of the motor. Fed its coils from an AC or DC source for producing field reverses the same for the stator to generates a torque that drives the rotor.

There are different types of it:

a. Squirrel cage (for AC motor) or the squirrel-cage rotor of the motor

b. Wound rotor (for AC motor) or the wound rotor of the motor

c. Armature (In DC motor) or the armature rotor of the motor
4. Bearings (in AC motor):
It aims to reduce friction between the shaft of the rotor and bearings loading. This is for:

reducing corrosion.
Increasing the lifespan of the rotor.
Reducing heat resulting from friction.

The development of science and industry has been produced by many different types that are suitable for different types of motors in different operating conditions.
5. Commutator (for DC motor):
It’s an important part you can find in DC motors, and its function is to reverse the current in the rotor coil to continue its rotation in one direction.

It is made of red copper.
6. Brushes (for DC motor):
Provides good communication between commutator and source.
7. Conduit box:
For the construction of the motor and used to connect power to stator coils.
8. Eye Bolt:
To assist carry the motor from it when we want to transport motor from place to another place. This is the basic structure of all motors, But simple differences are depending on the motor type.