, Z a = Z b = Z c, .. Ra = Rb = Rc = R Xa = Xb = Xc = X,
Ia = Ib = Ic = I = U / Z (3.12)
φa = φb = φc = φ = arctg (X/R) (3.13)
(. 3.8), , : İa + İb + İc = 0. , IN = 0, .
. 3.8
Z ab = Z bc = Z ca = Z ejφ (3.22)
.. Zab = Zbc = Zca = Z, φab = φbc = φca = φ.
( ) UAB, UBC, UCA ,
İab = Úab / Z ab; İbc = Úbc / Z bc; İca = Úca / Z ca.
, 120.
İA = İab - İca; İB = İbc - İab; İC = İca - İbc;
(.3.13, 3.14).
. 3.13
(. 3.14) φ (, , .. φ > 0). , UAB . , . İA İab 30, İB İbc, İC İca.
, U = U; I = I.
, .
U = U. I = U / Z, I = I, φ = arctg (X / R).
. 3.14
, Za ≠ Zb ≠ Zc φa ≠ φb ≠ φc
İa = Úa / Z a; İb = Úb / Z b; İc = Úc / Z c.
İN
İN = İa + İb + İc.
Ua = UA; Ub = UB; Uc = UC, U = U / , ZN = 0.
, .
, , . , , .
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. 3.9
. 3.9
:
Zab ≠ Zbc ≠ Zca. . , , . 3.15, , .
. 3.15
, ab , bc -, ca - . 3.16, . 3.17.
. 3.16
İA = İab - İca; İB = İbc - İab; İC = İca - İbc.
. 3.17
, İab, İb, İca , İA, İB, İC (3.20) (. 3.16, 3.17).
, , . , . .
İab, İbc, İca φab, φbc, φca. (3.20) (. 3.16, 3.17).
.
. 3.10.
. 3.10
, Z a = Z b = Z c = Zφ, N n , UnN = 0.
, .. U = U / , (3.12, 3.13), . . φ = arctg (X / R).
Z a ≠ Z b ≠ Z c UnN.
, 3.10 ,
(3.14)
: Y a = 1 / Z a; Y b = 1 / Z b; Y c = 1 / Z c .
, . ,
Úa = ÚA - ÚnN; Úb = ÚB - ÚnN; Úc = ÚC - ÚnN (3.15)
, :
İa = Úa / Z a = Y a Úa; İb = Úb / Z b = Y b Úb; İc = Úc / Z c = Y c Úc (3.16)
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, () UnN (. 3.11).
( ) UnN . n , Úa, Úb Úc .
, . , . Úa, Úb, Úc n ( ).
. 3.11
.
, :
;
.
, , .
3) ( ) X, Y Z N, ( ) (. 3.6). (Za, Zb, Zc) n. .
. 3.6
A − a, B − b C − c, , , N − n, N n , .
, .
. U (UA, UB, UC ; Ua, Ub, Uc ). , , . (UA = Ua, UB = Ub, UC = Uc). .
(U ) (UAB, UBC, UCA). , , (. 3.6).
:
(I ) .
(I ) .
I = I (3.5)
, , IN.
n (N)
İ N =İ A +İ B +İ C (3.6)
. 3.7
.
Ú AB =Ú A −Ú B; Ú BC =Ú B −Ú C; Ú CA =Ú C −Ú A (3.7)
. 3.7 , , : UAB, UBC, UCA 120 ( U ), , , UA, UB, UC, (U ) 30.
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(3.8), , :
U =2 U cos30
U = U (3.8)
:
U =660; U =380;
U =380; U =220;
U =220; U =127.
(. 3.7), . , , .
4) :
, Za ≠ Zb ≠ Zc φa ≠ φb ≠ φc
İa = Úa / Z a; İb = Úb / Z b; İc = Úc / Z c.
İN
İN = İa + İb + İc.
Ua = UA; Ub = UB; Uc = UC, U = U / , ZN = 0.
, .
, , . , , .
. 3.9
. 3.9
5) , . , ( ) (Z = 0, ZN = 0). Ua, Ub Uc ( ), .. Ua = UA; Ub = UB; Uc = UC. Z a = Z b = Z c,
İa = Úa / Z a; İb = Úb / Z b; İc = Úc / Z c (3.10)
İN = İa + İb + İc = İA + İB + İC (3.11)
6) :
. 3.10.
. 3.10
, Z a = Z b = Z c = Zφ, N n , UnN = 0.
, .. U = U / , (3.12, 3.13), . . φ = arctg (X / R).
Z a ≠ Z b ≠ Z c UnN.
, 3.10 ,
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(3.14)
: Y a = 1 / Z a; Y b = 1 / Z b; Y c = 1 / Z c .
, . ,
Úa = ÚA - ÚnN; Úb = ÚB - ÚnN; Úc = ÚC - ÚnN (3.15)
, :
İa = Úa / Z a = Y a Úa; İb = Úb / Z b = Y b Úb; İc = Úc / Z c = Y c Úc (3.16)
, () UnN (. 3.11).
( ) UnN . n , Úa, Úb Úc .
, . , . Úa, Úb, Úc n ( ).
. 3.11
.
, :
;
.
, , .