EE SHORT NOTES(ONE LINER)-TRANSFORMERS PART 1


1
In a transformer minimum voltage regulation
occurs when the power factor of the load is
leading
2
Current transformers for meters and relays
usually have
5-A secondaries
3
Increase in secondary current of a transformer
brings about increase in primary current. This is possible because
primary and secondary
windings are inductively coupled
4
The output current corresponding to the maximum
efficiency for a transformer having core loss of 200 W and equivalent
resistance referred to secondary of 0.5 ohm is
20 A
5
Burden of a current transformer is usually
expressed in
volt amperes
6
The yoke sections of transformers using
hot-rolled laminations is made 15 per cent greater than that of the core so
as to
to reduce the iron
loss in yoke and magnetizing current
7
The humming sound in a transformer is mainly due
to
magnetostriction
8
Spiral core transformer which has core made up of
steel strip has the following advantage.
Less weight,lighter construction,minimum losses
9
Which value of flux is involved in the e.m.f.
equation of the transformer ?
Maximum value
10
Which of the following insulating materials is
used in power transformers ?
Tapes of glass,press board,synthetic resin bonded paper.
11
In some transformers, the tapping are provided
on
H.V. side
12
Minimum voltage regulation occurs when the power
factor of the load is
leading
13
The hum in a transformer is mainly attributed to
magnetostriction
14
Which of the following protection is normally not
provided on small distribution transformers ?
Buchholz relay
15
In a power or distribution transformer about 10
per cent end turns are heavily insulated
to withstand the high
voltage drop due to line surge produced by the shunting capacitance of the
end turns
16
Natural air cooling is generally restricted for
transformers up to
1.5 MVA
17
Which type of winding is used in 3- phase
shell-type transformer ?
Sandwich type
18
An ideal transformer is one which has
no losses and magnetic
leakage
19
The full-load copper loss of a transformer is
1600 W. At half-load, the copper loss will be
400 W
20
Which of the following properties is not
necessarily desirable for the material for transformer core ?
High thermal
conductivity
EE SHORT NOTES(ONE LINER)-TRANSFORMERS PART 2
CURRENT AFFAIRS QUIZ OF DAY-7 MARCH 2017

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