璺 , U.
, 1000 1000 - .
, U=380 , . , , , , , 璺 .
. 380/220 , 50 . . , , 
=20 *. 
=17 .
7*7 . 40*40 , 2,5 , 0,75 . 璺 40*4 1.
1. . 1000 , 10 .
() 
.
2. 
.
, (5.1)
- , ; 
- , .
=5,23
3. 
, *, :
, (5.2)
- , (
=1,2).
=20*1,2=24 *
4. 
, . :
, (5.3)
- , ; d , ; 
- , .
ij :
d=0.95*b=0.95*0.04=0.038
b , .
=0,75+2,5/2=2
=7,94
5. () :
(5.4)
=7,94/5,23 
2
= / = 28/2,5 11,
, ; , .
, 11 .
6. 
=0,47.
7. :
= 
=1,54 (5.5)
8. 璺 :
, (5.6)
- , ; 
- , ; b , .
t=0,75+0,04/2=0,77
=0,51
9. 璺 :
|
|
|
, (5.7)
- 璺 ; 
- (
=0,19).
=0,51/(1*0,19)=2,68
10. :
= 
=0,98
R , 10 , 1 . :
=7,94
=2 .
, , 璺 .
