www.elektronik.si
 Frekvenca in napetost omrežja

 www.elektronik.si -> Energetika
Avtor: Umnik, Kraj: Novo mesto PrispevekObjavljeno: Ned Nov 14, 2004 11:31 pm    Naslov sporočila: icon_question Frekvenca in napetost omrežja
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Zanima me, zakaj uporabljamo sistem 50Hz in 230V?
Torej: zakaj točno frekvenca 50 Hz in ne kakšna druga; enako vprašanje velja tudi za napetost. Kakšne bi bile posledice uporabe drugačnih frekvenc in napetosti?
Vprašanje se je porodilo pri druženju nekaj elektronikov in strojnika. Po vseh teorijah, ki smo jih bili zmožni (Martin) spravit skupaj štirje dvajsetletniki, smo prišli do zaključka, da je (kot za vse) kriva država Laughing Je res?
Vmes pa so bile ideje, o težavah prenosa energije, mehanskih omejitvah in raznorazne neumnosti.
Avtor: .,  PrispevekObjavljeno: Pon Nov 15, 2004 8:47 am    Naslov sporočila:  
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Brisana vsebina odstranjenega uporabnika.
Avtor: Umnik, Kraj: Novo mesto PrispevekObjavljeno: Pon Nov 15, 2004 3:22 pm    Naslov sporočila:  
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Ok. Američani uporabljajo 120V/60Hz. (po tabeli na linku)
In spet vprašanje: zakaj točno 120V in 60Hz?

Heh...
Avtor: Highlag, Kraj: Črnuče PrispevekObjavljeno: Pon Nov 15, 2004 7:06 pm    Naslov sporočila:  
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Malo za zobat:

Se oproščam, ker ni v našem maternem jeziku, je pa vsekakor zanimivo.
Sneto iz Wikipedije

History of Voltage and frequency around the world

The system of three-phase alternating current electrical generation and distribution was invented by Nikola Tesla in the nineteenth century. He considered that 60 Hz was the best frequency for alternating current (AC) power generating. He preferred 240 V. This is claimed to be better for long supply lines. Thomas Edison developed direct current (DC) systems at 110 V and this is claimed to be safer.

The German company AEG built the first European generating facility to run at 50 Hz allegedly because the number 60 did not fit into the numerical unit sequence of 1, 2, 5…. At that time, AEG had a virtual monopoly and their standard spread to the rest of the continent. In Britain, differing frequencies proliferated, and only established the 50 Hz standard after World War II.

Not only is 50 Hz 20% less effective in generation, it is 10–15% less efficient in transmission. It requires up to 30% larger windings and magnetic core materials in transformer construction. Electric motors are much less efficient at the lower frequency, and must also be made more robust to handle the electrical losses and the extra heat generated. Nevertheless, today only a handful of countries (Peru, Ecuador, Guyana, the Philippines and South Korea) follow Tesla’s advice and use the 60 Hz frequency together with a voltage of 220–240 V.

Originally Europe was 110 V too, just like Japan and the US today. It has been deemed necessary to increase voltage to get more power with reduced loss and voltage drop from the same copper wire diameter. At the time the US also wanted to change, but it was deemed too costly to change all of the existing infrastructure.

Americans are still often stuck with the problems of the lower voltage. A device at 120 V draws twice as much current as a device with the same power draw at 240 V. A 3000 W electric dryer requires 12.5 A at 240 V or 25 A at 120 V. The end result is that wiring must be larger, and each outlet supplies less power. This may have been a factor in the use of circuit breakers in America long before they became common in Europe.

All new American buildings get 230 V split in two 115 V supplies between neutral and hot wire. Major appliances, such as dryers and ovens, are now connected to 230 V. Americans who have European equipment can connect it to these outlets, as long as it can accept the U.S. frequency of 60 Hz rather than 50 Hz.
Avtor: robertos, Kraj: Vuhred JN76OO PrispevekObjavljeno: Pon Nov 15, 2004 10:08 pm    Naslov sporočila:  
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MarE69 je napisal/a:
Od kje ti pa ideja, da se uporablja samo 50Hz in 220V? Sploh pa je pri nas 230V.


Standard pri nas v Sloveniji je res 230V in 50Hz ampak doma pa imam napetosti po fazah.:
L1= 240 V
L2= 241 V
L3= 239 V
Nekaj podobnega imamo tudi v Radioklubu na 1005nm, sploh pa vse napetosti v kraju kjer živim, iz različnih transformatorjev se gibljejo od 236 V pa do 243 V.
Merjeno z različnimi instrumenti analognimi in digitalnimi. Po klicu na elektro distribucijo zakaj je temu tako, pa so mi odgovorili, da sem pač doma 150m od transformatorja iz katerega je napajan tudi zadnji kmet, ki pa je oddaljen 10km. Da pride do njega 230 V ali morda celo manj, mora pač biti transformator nastavljen na višjo napetost.
Avtor: Umnik, Kraj: Novo mesto PrispevekObjavljeno: Tor Nov 16, 2004 1:46 am    Naslov sporočila:  
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Hvala Highlag za tale prispevek.
Moram reči, da sem se moral kar potrudit, da sem na internetu našel kaj materiala na to temo. Sem pa po iskanju našel en dober članek o tem, sicer razložen bolj na enostavno a vseeno. No, prevedel sem ga in stisnil sem: Klik
Mogoče pride komu prav.
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