ELECTRICAL DEPARTMENT NOTICE BOARD

MID SEM TEST SYLLABUS

SUBJECT : DESIGN OF DC MACHINES AND TRANSFORMER

SUBJECT CODE : 2160912

SEMESTER : 6^TH

Ch – 1 :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

Ch – 2 :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;

Ch -3 : 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;

                    

Question bank  (6Th semester)
Design of D C Machines & Transformer[ 2160912]
1	Derive an output equation of DC machines with usual notation
2	Briefly explain the factors affecting window space factor on transformer
3	Derive the relation between Emf per turn(Et) and transformer rating(Q)
4	How will the output and losses in transformer vary with linear dimensions?
5	How area of core is affected by weight of copper and iron.
6	Explain technical reasons for: 1.   Circular coils are preferred in transformer winding. 2.   Tapping’s are usually provided on H.V. Side of Transformer
7	From the design data discuss how no load current can be estimated in 3-phase core type transformer.
8	Derive the expression for finding leakage reactance of three phase core type Transformer.
9	The length of the air-gap is not uniform under the entire pole face. Why it is so?
10	Explain criteria for selection of specific loading in d c machine.
11	Write a short note on heating of electric machine.
12	Explain how pole body height is fixed while designing field system of a DC machines
13	Explain steps to design field winding of a D.C. machine.
14	Explain various factor affecting selection of number of poles for D.C. machine
15	List out diff. types of winding used in 3- phase transformer with its voltage rating. Also explain any one in detail
16	Explain the process of design of LV and HV winding of a transformer.
17	Explain the process of design of core of a transformer.
18	Explain effect of change in frequency on losses, voltage & leakage impedance    of transformer.
19	Explain various factors affecting selection of air gap length in dc machine.
20	Derive an expression of the number of Coils of DC machine armature from design parameter with usual notations
21	Explain guiding factors for choice of no of armature slots. Also show the slot  view with insulations
22	Explain diff. cooling methods used for oil immersed transformer
23	Explain : a. Significance of mitered joints in transformer. b. Design difference between power & distribution transformer.
24	Derive an output equation of single phase Transformer with usual notation
25	Derive an output equation of Three phase Transformer with usual notation