Difference Between Motor and Generator

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Difference Between Motor and Generator in Detail

An electric motor converts electrical energy into mechanical or kinetic energy, whereas the electric generator transforms the electric energy into mechanical/kinetic energy.

How can we compare and contrast motors and generators? We can do this by comparing them based on energy conversion.

Switching on the button of the fan or the AC button, and getting cool air during summers has the role of motors. Getting electricity supply during power off is possible because of generators.

In this article, we will learn to differentiate electric motor and generator.


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The Difference Between Electric Motor and Electric Generator in Tabular Form

Electric Motor 

Electric Generator 

Motor transform electrical energy into mechanical.

The generator transforms mechanical energy into electrical.

The motor uses electricity. It works on the principle that when a current-carrying conductor is placed in a magnetic field, it experiences a force and rotates.

The word ‘generator’ means to generate something, and an electrical generator produces (generates) electricity.


An electric generator works on the principle of electromagnetic induction or EMI.

We can determine the direction of force with the help of Fleming’s left-hand rule.


For example, when the armature of the motor rotates in a clockwise direction, the direction of the force will be upward. However, if it moves anticlockwise, the force will act downward. 

We can determine the direction of the induced current by using Fleming’s right-hand rule.


Since we are getting the output as electricity, we will determine the direction of the current by using Fleming’s right-hand rule. 

In electric motors, we use split rings or commutators.


These split rings are called the semicircular rings, they are made by cutting a copper ring into two halves. 

In electric generators, we use slip rings; these slip rings are two co-axial copper rings.

The shaft of the motor is driven by the magnetic force generated between the armature and the field.

In electric generators, the shaft is attached to the rotor and is driven by the mechanical force.

Example - An electric car or a bike is an example of an electric motor.

Example - Energy in the form of electricity is generated at power stations. The power stations, in turn, supply this electricity to the buildings in their area.


If we were to ask anything common between the electric motor and the electric generator, the similarities are as follows:

  • Both have magnetic field lines.

  • Both have armature coil placed between the magnetic poles viz: North and the South pole.

  • Both have carbon pressures.

  • Both have two brushes viz: b1 and b2.

Now, let’s understand Fleming’s right-hand rule and Fleming’s left-hand rule to distinguish between electric motor and electric generator.


Fleming’s Left-Hand Rule in Electric Motor

We know that motors convert electrical energy into mechanical energy and how this transformation occurs is a really interesting phenomenon. The force by which the motion occurs, can be better explained with the help of Fleming’s left-hand rule, and the statement for the same is as follows:


The electric and the magnetic field existing in electric motors lead to the motion of the armature coil. Now, let’s stretch our forefinger, middle finger, and thumb in such a way that they lie perpendicular to each other, as you can see below:


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So, the forefinger reflects the direction of the magnetic field, the middle finger points the direction of the current and the thumb represents the direction of motion of the armature coil of the motor.


Fleming’s Right-hand Rule in Electric Generator

We know that the electric generator generates electricity. The direction of the induced current can be easily understood by using Fleming’s right-hand rule. The statement for the same is as follows:


When a current-current conductor is attached to the circuit, it starts moving in a magnetic field. So, Fleming’s right-hand rule gives the direction of the flow of current.


The statement says when we stretch the index finger, middle finger, and thumb in such a way that they lie perpendicular to each other, then the index finger represents the direction of the magnetic field, the thumb points to the direction of motion of the conductor, and the middle finger reflects the direction of induced current.


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In day-to-day life, we can observe the working of an electric motor and the electric generator and then differentiate between electric motor and generator. So, let’s see one example for each to understand this differentiation.


Difference Between Electric Motor and Electric Generator

We find motors in electric fans, so when we switch on the button, the far starts moving. The energy by which it makes rotational motion is the kinetic energy, and kinetic energy is nothing but the mechanical energy. So, electric motors transform electric energy into mechanical energy.


When we rotate the arm of the generator, the electricity is supplied to the house. So, what we are doing is, we supplied mechanical energy to the generator and that energy transforms into electrical energy, which we utilize in switching on the fan and other electrical appliances during the electricity cut at home.

FAQ (Frequently Asked Questions)

Question 1: What is the Function of Split Rings in an Electric Motor?

Answer: The split ring is also called a commutator. Split rings reverse the direction of electric current in the armature coil. It’s because when the direction of the coil changes, the direction of the current has to be reversed to maintain the flawless rotation of the coil in the same direction.

Question 2: Among the Following Options What is the Phenomenon of Electromagnetic Induction?

  1. It is the process of charging a body.

  2. Is the process of generating a magnetic field because of the current passing through the coil.

  3. Generating induced current in a coil due to relative motion between a magnet and the coil.

  4. The process of rotating armature of the motor.

Answer: Option (2)

EMI is the phenomenon of generating induced current in the current-carrying coil due to a relative motion between the magnet and the coil.

Question 3: What is the Basic Difference Between the DC Generator and the AC Generator?

Answer: DC generator has slip rings, while the AC generator has a commutator.

Question 4: List the Devices in Which the Electric Motor is Used.

Answer: The following is the list of home appliances where an electric motor is used:

  • Grinder

  • MP3/DVD players

  • Washing machine

  • Mixers

  • Blender

  • Electric fans