what is a generator?

       Generator is a electrical machine with which we are generating electric energy for our daily needs. now a days life without electricity is impossible, each and every second we are depending upon electricity and electrical equipment which use electrical energy.

Generator:

       Generator can be defined as an electrical machine which converts mechanical energy into electrical energy. The electrical energy that is generated may be A.C or D.C depends upon generator that we are using to convert energy. We have both AC  and DC generators which generates AC and DC electrical energy respectively.

How generator works?

        Generator works on the principle of Faraday's electro magnetic induction principle. Faraday built first generator and named it as Faraday's disk  which is homopolar with a disk. Faraday's law states that " when ever a conductor cuts a magnetic field an EMF will be induced in the conductor and current will flow when conductor has closed path". Here we have to know one thing that is when conductor is cutting magnetic field which is steady then EMF will be induced. when conductor does not move we have to take magnetic field which cuts conductors. From this we got to know that one conductor or magnetic field must move to cut other not both.

Construction of generator?

        Generator construction consists of  7 essential parts;

1) Magnetic Frame or Yoke

2) Pole core and pole shoe

3) Pole coils and field coils

4) Armature core

5) Armature windings or conductors

6) Commutator

7) Brushes and Bearings

Yoke:

         The outer frame is called as Yoke which is used as mechanical support for complete generator and also used for holding poles. Electro magnetic poles will be attached to outer frame as it should give constant magnetic flux. Material used for Yoke is cast steel or rolled steel but in some small generators we can use cast iron also.

Pole core and Pole shoe:

        Pole core is attached to yoke along with pole shoe. Pole core will hold Field windings and give support to pole shoe to spread flux uniformly. Pole core is made up of cast iron or cast steel. Pole shoe will spread flux into air gap and also due to large cross section reduce reluctance to magnetic field.In most of generators both pole core and shoe will be laminated to reduce losses.

pole coils:

      Pole coil is an copper wire wounded around pole core. when current passes through pole coils or field coils then it electromagnetise the pole coil and produces necessary flux which cuts by conductors.

Armature core:

      Armature Core is the place where armature conductors will be placed. It will be cylindrical in shape and holds conductors to cut magnetic flux produced by field coil.It is completely laminated to reduce eddy current losses.

Armature Windings:

     Armature Windings are nothing but conductors placed in slot of Armature Core. It is former wound in rectangular coil and pulled to shape we wanted. It is completely laminated from each other and is short circuited at the end to form a completely closed circuit to produce current in windings.

Commutator:

    Commutator is used to collect current from armature conductors. Current from the armature conductors are collected by commutator and rectify it to unidirectional as current in armature conductors are bidirectional.

Brushes and Bearings:

    Brushes are used to collect current from commutator and it is made of copper or graphite. Bearings are used frequently for heavy duties and used for smooth movement which is placed in bearing bracket.

Brief working of Generator:

   Generator works when we give mechanical energy as input. mechanical energy can be given from renewable and non renewable sources. when mechanical energy is given it rotates the armature conductors and field pole produces magnetic flux with residual magnetism.then moving conductors cuts uniform magnetic flux then it produces EMF in conductors, as armature conductors are shorted to closed loop so current will flow in conductors which is collected by commutator which is rectified and that current will be collected by brushes to the load.

Generators in our daily life:

   Mainly generators are used to generate power in power plants and that is a big AC generators. Genarators are used where ever we are short of electricity. some of big companies are generating power by itself without getting from power plants.solar panels we use in our homes also use generators to convert to electrical energy. wind turbines in hilly areas uses generators to convert wind energy to electrical energy. coal, Gas, nuclear materials and Water in dams are used to generate electrical energy.

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