Техническое чтение для энергетиков. Бухарова Г.П. - 61 стр.

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63
each turn of the winding providing its own proper proportion of the total volt-age.
The alternating magnetic flux also induces an e.m.f. in the turns of the secondary
winding, the volts per turn being the same for both windings.
In actual practice, the induced e.m.f. in the primary windings is very slightly less than
the applied voltage, on account of voltage drops in the circuit. Similarly, the induced
e.m.f. in the secondary windings is very slightly greater than the secondary terminal
voltage, when the transformer is delivering a load current, for the same reason. The
voltage ratio is therefore slightly greater than the turns ratio.
* as a piece of apparatus как прибор; piece употребляется в качестве счётного слова для
указания на отдельный предмет. Обычно в подобном сочетании на русский язык не
переводится.
EQUIVALENT CIRCUITS
An actual transformer may be represented, for purposes of explanation, as consisting
of an ideally perfect transformer, having no losses or magnetizing current, together
with various additions to allow for these effects.
Fig. 13. Equivalent Circuits of a Transformer
Fig. 13. represents such an ideal transformer having a resistance, R
1
, and a reactance
X
1
, in series with its primary winding, and a resistance, R
2
, and a reactance, X
2
, in
series with its secondary winding. The no-load current has both an active and a
reactive component The latter is the magnetizing current of the iron core, I
m
, and is
represented in the diagram by the current flowing through an additional reactance,
while the active component, I
c
, supplying the iron losses in the core, is represented by
the current flowing through an additional resistance. The vector resultant of I
m
and I
c
is I
0
, which is the total no-load current of the transformer. The secondary current is I
2
,
and the component of the primary current that neutralizes I
2
is I'
1
The total primary
current, I
1
, is the vector sum of this component, I'
1
, and the no-load current, I
2
. The
turns in the primary and secondary windings are T
1
and T
2
respectively, and are so
related that
ratioturnsn
T
T
I
I
===
2
1
'
1
2
The flux Ф is the useful flux linking both primary and secondary windings. The
induced secondary e.m.f. is E
2
, this being slightly greater than the secondary terminal

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