Environmental Engineering Reference
In-Depth Information
(5.93)
In contrast to the transformer, the rotor winding of an asynchronous machine,
which corresponds to the secondary windings of the transformer, is short-
circuited (
V
'
2
= 0). The rotor frequency
f
2
of an asynchronous machine is
different from the frequency
f
1
of the stator. The slip
s
of the machine connects
both frequencies:
(5.94)
The reactances of the rotor circuit become:
(5.95)
If
X
'
2σ
and
X
h
in the voltage equations of the secondary site are replaced by
s
·
X
'
2σ
and
s
·
X
h
, respectively, and
V
'
2
= 0 is used, the equation for the rotor
becomes:
(5.96)
The splitting
(5.97)
provides the
equivalent circuit
for one phase of the asynchronous machine (see
Figure 5.28).
With
X
'
2
=
X
'
2σ
+
X
h
and the voltage equation of the rotor, the current
becomes:
(5.98)
Figure 5.28
Equivalent Circuit for One Phase of an Asynchronous Machine
