Prepared By:- Nisarg Amin

Topic:- Flowchart For Optimal Design Of DC Machine And Transfomer

Flowchart For Optimal Design Of DC Machine

Construction Of A DC Machine

Construction of DC Machine

• Yoke : It provide mechanical Support for poles & protection.

• Pole Shoe : It is extended part of pole & enlarge area of pole.

• Field Winding : When Current is passed through field winding it electro magnetize the poles which produce necessary flux.

• Armature Core & Winding : It provide path of low reluctance to the flux produced by field winding & when armature winding is rotated using prime mover. the magnetic flux and voltage gets induced in it.

• Commutator : It Convert alternating current, collects the current form armature conductor and pass it load with the help of brushes & provide unidirectional torque for dc motor.

Working Principle

• In a basic dc motor, an armature is placed in between magnetic poles. If the armature winding is supplied by an external dc source, current starts flowing through the armature conductors.

• As the conductors are carrying current inside a magnetic field, they will experience a force which tends to rotate the armature. Suppose armature conductors under N poles of the field magnet, are carrying current downwards (crosses) and those under S poles are carrying current upwards (dots).

• By applying Fleming’s Left hand Rule, the direction of force F, experienced by the conductor under N poles and the force experienced by the conductors under S poles can be determined. It is found that at any instant the forces experienced by the conductors are in such a direction that they tend to rotate the armature.

APPLICATION

• DC Shunt Motors is a constant speed motor. (Lathes, Drills, Boring mills, Shapers, Spinning and Weaving machines)

• DC Series motor is a variable speed motor. (Electric traction, Cranes, Elevators, Air compressor, Vacuum cleaner, Hair drier, Sewing machine)

• DC Compound motor, thedifferential compound motors are rarely used because of its poor torque characteristics. (Presses Shears, Reciprocating machine)

Disadvantages

• High initial cost

• Increased operation and maintenance cost due to presence of commutator and brush gear

• Cannot operate in explosive and hazard conditions due to sparking occur at brush ( risk in commutation failure)

Flowchart For Optimal Design Of Transformer

Introduction

• Transformer is a device consisting of two or more coils that are used to couple electrical energy from one circuit to another while maintaining electrical isolation between the two.

• Primary Winding – Winding of the transformer that is connected to the source.

• Secondary Winding – Output winding of the transformer that is connected to the load.

Working Principle

• Mutual inductance

• Mutual Inductance – The ability of one inductor’s magnetic field lines to link with another inductor.

Transformer action

Classification of transformer

• As per phase:

1. Single phase

2. Three phase

• As per core:

1. Core type

2. Shell type

• As per cooling system:

1. Self-cooled

2. Air cooled

3. Oil cooled

Step up transformer

• A step up transformer is a type of transformer that increases voltage from primary to secondary (more secondary winding turns than primary winding turns) is called a step up transformer.

Step down transformer

• A step down transformer is a type of transformer that decreases voltage from primary to secondary (less secondary winding turns than primary winding turns) is called a step down transformer.