What is Electrical Machines, Motor, Generator, Transformer

Hello guys welcome to my blog. Hope you are all good and well. 

Today we will discuss about,

  • What is electrical machines?
  • Types of electrical machines
  • What is motor?
  • What is generators?
  • What is transformers?
  • Applications for motor
  • Applications for generators
  • Applications for transformer

What is electrical machines: -

The device which converts the mechanical power into electrical power or electrical power into mechanical power is known as electrical machine.
A machine which transforms electrical power from one circuit to another circuit is also known as a electrical machine.

Types of electrical machines: -

There are mainly two types of electrical machine on the basis of supply power: -
  • DC machine 
  • AC machine

Now let's come to learn in brief about these machines. 

DC machines: -

A DC machine is the type of machine which works on the DC supply. 
This machine may convert DC electrical power to mechanical power or vice versa. 


Types of DC machines: -

There are mainly two types of DC machines: -
1. DC generators
2. DC motors

DC generator: -

If machine converts the mechanical power into DC electrical power, then it is called DC generator. 

Working principle of DC generator: -

The DC generator works on the principle of electromagnetic induction, which states that if a conductor moving in a magnetic field, it will cut the magnetic field lines and a dynamically induced emf will produce in the conductor. 

Working on DC generator: -

  • There are mainly two windings in a DC generator, one of them is called field winding and the other is called armature winding. 
  • When the field winding is connected to a DC supply, it will produce a magnetic field. 
  • Under this magnetic field armature rotates and cuts the magnetic field of lines. 
  • Hence an emf will produce according to Faraday's law of electromagnetic induction. 
  • If the circuit is close, then a current will flow through the armature winding. 

Note: -
Armature windings are connected to the load with the help of the commutator. 

Types of DC generator: -

According to methods of field excitation there are mainly two types of DC generators: -
1. Separately excited DC generator
2. Self excited DC generator

Separately excited DC generator: -

A DC generator in which field winding is supplied from an external DC source is known as a separately excited DC generator. 

Self excited DC generator: -

A DC generator in which field winding is supplied from the generator itself is known as a self excited DC generator. These are further classified into three types: -

1. Shunt wound DC generator
2. Series wound DC generator
3. Compound wound DC generator. 

Applications of DC generators: -

  • They are mainly used for power supply purpose. 
  • They can be used in DC locomotives for regenerative breaking purposes. 
  • They can also be used as a series booster for increasing the DC voltage across a feeder. 

DC motors: -

A DC motor is an electrical machine which converts the DC electrical input power into output mechanical power. 

Working principle of DC motor: -

It works on the principle on that whenever a current carrying conductor is placed in a magnetic field, it will experience a force. 

Working of DC motor: -

  • Like a DC generator, it also consists two windings, one of them is field and the other is armature winding. 
  • The field winding is excited by a DC source to produce a magnetic field.
  • The armature is placed in this magnetic field and it is also connected to a DC source through commutator. 
  • As we have studied that whenever a current carrying conductor (armature) placed in a magnetic field (produce by field winding) a force is experience by it and starts rotating. 


Types of DC motors: -

Like a DC generator, DC motors are of two types: -
1. Self excited DC motor
2. Series excite DC motor: -
  • Shunt motor
  • Series motor
  • Compound motor

Applications for DC motor: -

  • Electric fans
  • Sewing machines
  • Air compressors
  • Cranes 
  • Elevators etc. 

AC machines: -

An AC machine is the type of machine which works on the AC supply. 
This machine may convert AC electrical power to mechanical power or vice versa. 

Note: -
A machine which transforms AC electrical power from one circuit to another circuit is also known as AC machine. 

Types of AC machines: -

There are mainly three types of AC machines as given below: -
1. AC generators
2. AC motors
3. Transformer

What is AC generator: -

A machine which converts mechanical input power into AC electrical output power is known as an AC generator.

Working principle of AC generator: - 

Like a DC generator it also works on the principle of Faraday's law of electromagnetic induction. 

Working on AC generator: -

  • It also consists of two windings, one of them is known as field winding and the other is known as an armature winding. 
  • In this field winding is placed on the rotor and armature windings are placed on the stator.
  • The rotor is connected to a DC source which will produce magnetic field and rotate by a prime mover.
  • Now this rotor will rotate, also magnetic field will also rotate, this magnetic field will cut the armature conductors  and an emf will produced in the armature conductors. 
  • If the circuit is close a current will flow through it. 


Applications of AC generators: -

These generators are used in power station to generate large electrical power stations. 
Like diesel power stations, hydro power stations, and thermal power stations etc. 

What is AC motors: -

An AC motor is an electrical machine which converts the AC electrical input power into output mechanical power. 

Working principle of AC motors: -

Its principle is same as the DC motor working principe, i.e. 

It works on the principle on that whenever a current carrying conductor is placed in a magnetic field, it will experience a force. 

Types of AC motors: -

There are two types of AC motors: -
i). Synchronous motor
ii). Induction motor

i). Synchronus motor: -



ii). Induction motor: -

This is the most common type of Ac motor. It converts AC electrical power into mechanical power. 

Read: - Induction motor in brief.

3. What is transformers: -

A transformer is a static device which transfer the power from one circuit to another circuit without change in frequency. 

What is Electrical Machines, Motor, Generator, Transformer
Fig. Transformer

Working principle of transformer: -

It works on the principle of electromagnetic induction. 

Working of transformer: -

  • There is a core on which two windings are placed one of them is called primary winding and other is called secondary windings.
  • The AC supply is given to the primary winding and a flux is produced. 
  • This flux will link with a secondary winding through a transformer core and an emf will produce in the secondary winding according to Faraday's law of electromagnetic induction.
  • If the circuit is close, then a current will flow through it. 

Types of transformer: - 

There are various types of transformers, but most common types are: -

  • Step up transformer: -
The transformer in which the output voltage is more than the input voltage is known as a step up transformer. 

  • Step down transformer: -
The transformer in which the output voltage is less than the input voltage is known as a step down transformer. 


Applications for transformer: -

  • Transformers are used to increase or decrease the voltage level of the supply.
  • Used to isolate the electrical circuit.

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