# Design of DC Machines & Transformer - [2160912]

#### Teaching Scheme

 Theory Tutorial Practical Total 3 0 2 5

#### Examination Scheme

 Theory Examination Practical Examination Total ESE (E) PA (M) ESE Viva (V) PA (I) 70 30 30 20 150

ESE = End Semester Examination, PA = Progressive Assessment

#### GENERAL DESIGN ASPECTS:

Specific electric loading and Specific magnetic loading; Output coefficient; Output equations for transformers and rotating machines; Factors affecting size of machines; Criteria for selection of specific loadings; Heating and Cooling of Transformers and rotating machines.

#### DESIGN OF THREE PHASE TRANSFORMER

Types of transformers; Position of HV and LV windings and its importance; Relation between core and yoke cross section area and its significance; Different types of transformer windings; Different positions of taping; Window space factor; Factors affecting window space factor; Relation between emf per turn and transformer rating; Stacking factor.

#### MAIN DIMENSIONS:

Design of window dimensions, yoke dimensions and overall core dimensions; Numerical examples.

#### DESIGN OF WINDINGS:

Design of HVand LV windings (No. of turns and area of cross section); Selection of type of winding.

#### PERFORMANCE PARAMETERS ESTIMATION

Primary and secondary winding resistance and Leakage reactance calculation; Calculation of no load current, losses and temperature rise of transformer; Design of tank with tubes; Calculation of dimension of tank; Numerical examples. Variation of output and losses in transformer with linear dimensions; Basic design aspects of dry transformer and high frequency transformers. Basic design aspects of welding transformers and instrument transformers

#### DESIGN OF DC MACHINES:

Introduction; Output equation; MMF calculation; Selection of number of poles; Design of core length and armature diameter; Carter’s fringing curves and its significance; Design of length of air gap; Numerical examples.

#### ARMATURE DESIGN:

Choice of armature winding; Armature conductor; Number of armature slots; Slot dimensions; Slot loading; Design of armature core; Numerical examples.

#### DESIGN OF FIELD SYSTEMS:

Pole design; Design of field winding of shunt, series and compound machines; Design of inter poles; Effects and minimization of armature reaction; Design of commutator and brushes; Numerical examples. Performance parameters evaluation.

#### Reference Books

1A course in electrical machine DesignA. K. SawhneyDhanpat Rai & Co.
2Electrical Machine DesignR. K. AgrawalS K Kataria and Sons
3Design of Electrical MachineV. N. MittleSTANDARD PUBLISHERS DISTRIBUTORS

#### Course Outcome

After learning the course the students should be able to:

• Design the DC machine of given specifications.
• Design the transformers of given specifications.
• Prepare the detailed sketches of the designed machines.