PART A(10*2=20)
1. Give
an emf equation of DC generator.
2. Give
the conditions to build up voltage in shunt generator.
3. Why
series motor canot be started without any load?
4.
Define back emf.
5. Why
starter is necessary?
6.
Mention the applications of DC series motor.
7.
Define voltage regulation in a transformer.
8.
Distinguish between core
and shell type transformer
9.
Why transformers are rated
in KvA?
10.
Define al day efficiency.
PART
B (13*5=65)
11.
Explain briefly the characteristics of DC motor. (13)
12. List
he different method of sped control of
DC Shunt motor?(13)
13
Explain briefly the construction of
transformer(13)
14. (i)
Draw the equivalent circuit
of a transformer (7)
(ii).Draw the vector diagram of
transformer on load with different power factors.(6)
15.
(i). A 4 pole d.c shunt generator with a wave wound armature has to supply a
load of 50 lamps
each
of 10W at 250 V. allowing 10V for the voltage drop in the connecting leads
between the
generator
and the load and drop of 1 voltage per brush, calculate the speed at which the
generator
should
be driven. The flux per pole is 30mW and armature & shunt field resistances
are
respectively
0.05Ω & 65Ω. The number of armature conductor is 390.(7)
(ii). A single phase 20/250V, 50Hz transformer has a net
core area of 36 cm2 and a maximum
flux density
of 6 Wb/m2. Calculate the number of turns of primary and secondary.(6)
PART
C (15*1=15)
16. With
a neat sketch, explain the construction and working principle of DC Motor and
explain each
Parts. (15)
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