Motor

 Motor :

             A motor is nothing but an electro-mechanical device that converts electrical to mechanical energy.

Types of Motor :

* DC motor

* AC motor

* Special motor

In AC motor, have synchronous motor and single phase Induction motor.

In special motor, have Induction motor and 3phase Induction motor.

- The speed of these motor are varied by varying the frequency (f) and number of poles(p) as

        Ns = 120×F÷P

- Synchronous motor are not self starting

- Induction motor is also called as Asynchronous motor, Induction motor doesn't require any starting device their are self starting motor.

In motor we have,

Rotor :

          In motor the moving part is the rotor which turns the shaft to deliver the mechanical power. The rotor usually has a conductor coil into which carry current that interact with the magnetic field of the stator to generate the force that turn the shft. Some rotor carry permanent magnetic and the stator holds the conductor.

Stator :

            The stator is the stationary part of the motor electromagnetic current and usually consists of either winding (or) permanent magnet. The stator core is made up of many their metal sheets called lamination. Lamination are used to reduce energy losses that would result if a solid Core were used.

AIR GAP : 

              The distance between the rotor and stator is called the Air Gap.

Winding :

             Winding are copper wires that are laid in cort, usually wrapped around a lamination with soft iron magnetic core. So as to form magnetic poles when energized with current.

For construction site :-

Working principle of motor is based on femins left hand rule.

Types of motor as per NEMA(Natural Electrical Manufacturers Association). Their are 4 types of motor.

1) Type A motor - It will consume 5 to 8 times of exterior current.

2) Type B motor - It will consume 3 to 5 times of exterior current.

3) Type C motor - It will consume 5 to 6 times of exterior current.

4) Type D motor - It will consume 3 to 4 times of exterior current.

Type A & B are used for residential and commercial building.

Type C & D are used for industries.

Type B is best for residential and commercial building.

Type D is best for industries.

If the motor faults (or) not working their are three types of test should be done.

1) Continuity test :

    In this test will be done with the help of clamp meter, we have to check voltage, current and frequency.

2) Winding test :

    No load current = full load current×0.2

   We use multimeter to check R,Y,B.

3) Check the all parts (or) Hardware test.

Figure :

Working principle of motor