Difference Between Motor and Generator

Both the motor and generator comes under the machine category. The major difference between Motor and Generator is that a motor converts electrical energy into mechanical energy, whereas the generator does the exact opposite. The motor uses electricity whereas the generator produces electricity. Let us now understand more about the difference between motor and generator by going into their basics.

What is Motor?

A motor is a form of electrical machine that converts electrical energy into mechanical energy. Electric motors take power either from direct currents (DC) sources, such as from batteries, motor vehicles, or rectifiers or from alternating current (AC) sources, such as a power grid, inverters, or electrical generators.

What is a Generator?

A generator operates with a reversed flow of power, converting mechanical energy into electrical energy.

Difference Between Motor and Generator

The important difference between motor and generator

Parameter	Motor	Generator
Definition	Electric motors convert electrical energy into mechanical energy.	Generators convert mechanical energy into electrical energy.
Law	Flemings’ left-hand rule is followed to know the direction of motion.	Fleming’s right-hand rule is followed to know the direction of produced electricity.
Source of energy	Power grids, electrical supply.	steam turbines, water turbines, internal combustion engines.
Current	In motors, the current has to supply to armature windings.	In generators armature windings produce current.
EMF	The electric motor gives outback emf to the circuit.	The generator gives emf to the load connected.
Use	Automobiles, elevators, fans, pumps, etc.	In power supply chains in industries, testing purposes in the laboratory, general lighting, powering of batteries, etc.
Types	DC Brushed Motors, DC Brushless Motors, AC Brushless Motors, Direct Drive, Linear Motors, Servo Motors, Stepper Motors.	3 main types of generators: portable, inverter, and standby.

After learning about the difference between motor and generator, it is important to know the details of voltage and current thoroughly.

Motor

Motor functions by the coordination between the motor’s magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor’s shaft.

An electric motor works on a continuous rotation, or for linear movement over a significant distance compared to its size. It operates on three different physical principles: magnetism, electrostatics, and piezoelectricity.

Classification of Motor

AC Motor

It simply converts the alternating current into mechanical power. We further classify it into three types; they are the induction motor, synchronous motor, the linear motor.

1)Induction motor is further classified:

– on the basis of the rotor, the Squirrel Cage Rotor, and Phase Wound Rotor.

– on the basis of phase, Single phase induction motor, and Three-phase Induction Motor.

2) Linear motor.

3) Synchronous Motor, which is further classified as:

– Reluctance Motor.

– Hysteresis Motor.

DC Motor

It converts DC electrical power into mechanical power. It is divided into 2 major types

1) Separately Excited Motor.

2) Self-Excited Motor- This is further classified as;

– Shunt motor, Series motor, Compound wound motor, Short Shunt motor, Long Shunt motor.

Generators

The generator turns mechanical energy into electrical power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, etc. There are 2 broad categories of Electromagnetic generators. They are dynamos and alternators.

1) Dynamos generate a pulsing direct current through the use of a commutator.

2) Alternators generate alternating current.

Specialized types of generator

Direct current (DC)

A dynamo uses commutators to produce direct current. It is self-excited.

1) One such type is the Homopolar generator. This is a DC electrical generator consisting of an electrically conductive disc or cylinder rotating in a plane perpendicular to a uniform static magnetic field.

2) Another one is (MHD) generator. It directly extracts electric power from moving hot gases through a magnetic field, without the use of rotating electromagnetic machinery.

Alternating current (AC)

 1) The induction generator mechanically turns their rotor faster than the synchronous speed, giving a negative slip.

2) Linear electric generator- In this form, a sliding magnet moves back and forth through a solenoid – a spool of copper wire, which in turn induces an alternating current into the loops of wire.

3) Variable-speed constant-frequency generators- These generators are in use to harvest natural sources of mechanical energy (wind, tides, etc.) to produce electricity.

FAQs about Motor and Generator:

Q.1. Is it possible to run an electric motor as a generator in reverse?

Ans- Yes practically any type of motor can also serve as a generator. For example, a DC motor when runs in reverse supply current form the positive terminal. Similarly, asynchronous motor (including permanent magnet) produces power if run by an engine.

Q.2. Why generator efficiency is more than motor?

Ans- The efficiency of a generator is always greater than that of the motor. It is because the leakage of magnetic flux produces power losses in a motor but the leakage of the flux produced by the field winding in the generator is minimum. Hence there is no problem to lose some flux in the generator.