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Zbirka rešenih nalog - LES - Univerza v Ljubljani

Zbirka rešenih nalog - LES - Univerza v Ljubljani

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2 2<br />

Nadomestno vezje in kazalčni diagram transformatorja<br />

2<br />

⎛ U ⎞<br />

1n 240<br />

R ′<br />

⎛ ⎞<br />

b<br />

= Rb ⋅ p = Rb<br />

⋅ ⎜ ⎟ = 0,5 ⋅ = 50 Ω<br />

U<br />

⎜<br />

2n<br />

24<br />

⎟ . (5)<br />

⎝ ⎠ ⎝ ⎠<br />

Najlažje bo, da izračunamo tok, ko je transformator obremenjen s tem bremenom:<br />

I<br />

′<br />

U<br />

U<br />

240<br />

1n<br />

1n<br />

1<br />

= I2<br />

= = = =<br />

Z<br />

2 2<br />

2 2<br />

( R (2 50) 4,363<br />

k<br />

+ R ′<br />

b<br />

) + X + +<br />

k<br />

4,6 A , (6)<br />

z znanim tokom in upornostjo bremena pa nato dobimo sekundarno napetost:<br />

U ′<br />

2<br />

= I ′<br />

2<br />

⋅ R ′<br />

b<br />

= 4,6 ⋅ 50 = 230 V . (7)<br />

Ker je to napetost v nadomestnem vezju, ki upošteva prestavo ena, je potrebno le-to še<br />

preračunati na sekundarno stran:<br />

U<br />

U ′<br />

230<br />

10<br />

2<br />

2<br />

= = = 23 V . (8)<br />

p<br />

Generatorji in transformatorji - zbirka rešenih <strong>nalog</strong> 34

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