四、简化等效电路和相量图(忽略 r
a
):
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I
0
⋅
E
⋅
U
a
r
I
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U
⋅
I
ϕ
t
x
I
j
U
E
.
.
.
0
+
=
t
x
0
⋅
E
t
x
I
j
⋅
⋅
I
0
⋅
E
⋅
U
⋅
U
⋅
I
ϕ