{"id":2282,"date":"2024-09-05T12:58:43","date_gmt":"2024-09-05T10:58:43","guid":{"rendered":"https:\/\/gezhi-tech.com\/?p=2282"},"modified":"2025-09-27T17:50:23","modified_gmt":"2025-09-27T15:50:23","slug":"clause-3-how-to-understand-the-definition-of-safety-extra-low-voltage","status":"publish","type":"post","link":"https:\/\/gezhi-tech.com\/ro\/clause-3-how-to-understand-the-definition-of-safety-extra-low-voltage\/","title":{"rendered":"Clauza 3 \u2013 Cum s\u0103 \u00een\u021belege\u021bi defini\u021bia \u201etensiune foarte joas\u0103 de siguran\u021b\u0103\u201d"},"content":{"rendered":"tensiune foarte joas\u0103 de siguran\u021b\u0103: tensiune care nu dep\u0103\u0219e\u0219te 42 V \u00eentre conductori \u0219i \u00eentre conductori \u0219i p\u0103m\u00e2nt, tensiunea \u00een gol nu dep\u0103\u0219e\u0219te 50 V C\u00e2nd se ob\u021bine o tensiune foarte joas\u0103 de siguran\u021b\u0103 de la re\u021beaua de alimentare, aceasta se va face printr-o izola\u021bie de siguran\u021b\u0103. transformator sau un convertor cu \u00eenf\u0103\u0219ur\u0103ri separate, a c\u0103rui izola\u021bie respect\u0103 cerin\u021bele de dubl\u0103 izola\u021bie sau de izola\u021bie \u00eent\u0103rit\u0103.
NOTA 1 Limitele de tensiune specificate se bazeaz\u0103 pe presupunerea c\u0103 transformatorul de izola\u021bie de siguran\u021b\u0103 este alimentat la tensiunea nominal\u0103.
NOTA 2 Tensiunea foarte joas\u0103 de siguran\u021b\u0103 este cunoscut\u0103 \u0219i ca SELV.<\/em>
\nDin denumirea – siguran\u021b\u0103 foarte joas\u0103 tensiune, aceast\u0103 defini\u021bie are cuv\u00e2ntul \u201esiguran\u021b\u0103\u201d mai mult dec\u00e2t foarte joas\u0103 tensiune. Cu toate acestea, \u00een acest standard, am explicat anterior c\u0103 conceptul de siguran\u021b\u0103 este un concept relativ, care a fost explicat \u00een Prefa\u021b\u0103-1<\/a>. \u00cen acela\u0219i timp, \u201esiguran\u021ba\u201d definit\u0103 \u00een aceast\u0103 clauz\u0103 nu \u00eenseamn\u0103 siguran\u021b\u0103 absolut\u0103, astfel \u00eenc\u00e2t SELV s\u0103 poat\u0103 fi atins direct de utilizatori. Numai circuitele SELV care \u00eendeplinesc cerin\u021bele sec\u021biunii 8.1.4 pot fi atinse de utilizatori. Aceast\u0103 tensiune se ob\u021bine \u00een general prin sc\u0103derea tensiunii printr-un transformator de izolare de siguran\u021b\u0103 sau un convertor cu o \u00eenf\u0103\u0219urare separat\u0103. De obicei, se ob\u021bine printr-un transformator de izolare de siguran\u021b\u0103. Transformatorul de izolare de siguran\u021b\u0103 sau convertorul cu o \u00eenf\u0103\u0219urare separat\u0103 aici poate asigura c\u0103 \u00eenf\u0103\u0219urarea primar\u0103 \u0219i \u00eenf\u0103\u0219urarea secundar\u0103 sunt separate fizic \u00een structur\u0103, adic\u0103 \u00eenf\u0103\u0219ur\u0103rile primare \u0219i secundare nu vor fi \u00een contact direct; un exemplu comun al metodei de reglare a tensiunii care corespunde acestei separ\u0103ri de circuit prin \u00eenf\u0103\u0219ur\u0103ri separate este metoda RC step-down, care const\u0103 \u00een conectarea unui rezistor \u0219i a unui condensator \u00een paralel \u00een serie la circuitul de 220V. \u00cen metoda de reducere RC, partea de \u00eenalt\u0103 tensiune \u0219i partea de joas\u0103 tensiune sunt conectate \u00een circuit. Evident, prima metod\u0103 de separare a circuitului prin mijloace fizice este mai sigur\u0103. Dac\u0103 este doar o simpl\u0103 separare fizic\u0103, \u00eenc\u0103 nu poate \u00eendeplini cerin\u021bele de siguran\u021b\u0103. Izolarea cerut\u0103 de standard trebuie s\u0103 \u00eendeplineasc\u0103 cerin\u021bele de izolare dubl\u0103 sau de izolare armat\u0103. Mai simplu spus, dac\u0103 exist\u0103 o izola\u021bie foarte simpl\u0103 \u00eentre partea de \u00eenalt\u0103 tensiune \u0219i partea de joas\u0103 tensiune – cum ar fi o foaie de plastic sub\u021bire cu rezisten\u021b\u0103 la temperatur\u0103 sc\u0103zut\u0103, aceast\u0103 izola\u021bie este u\u0219or de defectat \u00een condi\u021bii de temperatur\u0103 ridicat\u0103 sau de \u00eenalt\u0103 tensiune \u0219i practic nu poate joac\u0103 un rol izolator, de\u0219i acest strat de folie de plastic separ\u0103 \u0219i fizic circuitele de \u00eenalt\u0103 tensiune \u0219i de joas\u0103 tensiune. Cerin\u021bele de izolare ale izola\u021biei duble \u0219i ale izola\u021biei armate sunt, de asemenea, un mijloc de dubl\u0103 protec\u021bie.
\n
\nAici, trebuie s\u0103 ad\u0103ug\u0103m c\u0103 SELV are reglement\u0103ri privind valorile tensiunii. Tensiunea specificat\u0103 aici este valoarea efectiv\u0103 a tensiunii. De obicei, valoarea de v\u00e2rf a tensiunii este mai mare dec\u00e2t valoarea efectiv\u0103, iar limita de tensiune specificat\u0103 \u00een clauza 8.1.4 este cerin\u021ba pentru valoarea de v\u00e2rf. Vom explica cerin\u021bele sale de testare \u00een detaliu \u00een clauza 8.1.4. Nota 2 din primul paragraf din clauza 3 ofer\u0103 propozi\u021bia \u201eNOTA 2 C\u00e2nd se folosesc termenii \u201etensiune\u201d \u0219i \u201ecurent\u201d, ace\u0219tia sunt valori efective, dac\u0103 nu se specific\u0103 altfel.\u201d
\n
\nA\u0219a cum se arat\u0103 \u00een figura de mai jos, transformatorul are trei suporturi de plastic plasate vertical \u00een disc pentru a separa \u00eenf\u0103\u0219ur\u0103rile primare \u0219i secundare (\u00eenf\u0103\u0219ur\u0103rile primare \u0219i secundare sunt \u00eenf\u0103\u0219urate cu band\u0103 de plastic albastr\u0103 pe exterior), iar \u00eenf\u0103\u0219ur\u0103rile primare \u0219i secundare sunt izolat fizic.
\n

\n\"\"
\n<\/figure>
\nA\u0219a cum se arat\u0103 \u00een figura de mai jos, transformatorul are band\u0103 galben\u0103 \u00eenf\u0103\u0219urat\u0103 \u00een jurul \u00eenf\u0103\u0219ur\u0103rilor primare \u0219i secundare din mijloc. Trebuie s\u0103 acord\u0103m o aten\u021bie deosebit\u0103 distan\u021bei de curgere a suportului negru dintre cele dou\u0103 \u00eenf\u0103\u0219ur\u0103ri pentru a vedea dac\u0103 poate \u00eendeplini cerin\u021bele privind distan\u021ba de curgere pentru izola\u021bia \u00eent\u0103rit\u0103. Dac\u0103 nu, transformatorul nu poate fi considerat un transformator de izolare de siguran\u021b\u0103.
\n

\n\"\"
\n<\/figure>
\nVom explica \u00een detaliu structura transformatorului de izola\u021bie de siguran\u021b\u0103 \u00een urm\u0103torul post.
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tensiune foarte joas\u0103 de siguran\u021b\u0103: tensiune care nu dep\u0103\u0219e\u0219te 42 V \u00eentre conductori \u0219i \u00eentre conductori \u0219i p\u0103m\u00e2nt, tensiunea \u00een gol nu dep\u0103\u0219e\u0219te 50 V C\u00e2nd se ob\u021bine o tensiune foarte joas\u0103 de siguran\u021b\u0103 de la re\u021beaua de alimentare, aceasta se va face printr-o izola\u021bie de siguran\u021b\u0103. transformator sau un convertor cu \u00eenf\u0103\u0219ur\u0103ri separate, a…<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"footnotes":""},"categories":[5],"tags":[167,74,76,89,77,90,91,163,75],"class_list":["post-2282","post","type-post","status-publish","format-standard","hentry","category-terms-and-definitions","tag-8-1-4","tag-insulation-applied-to-live-parts-to-provide-basic-protection-against-electric-shock","tag-insulation-system-comprising-both-basic-insulation-and-supplementary-insulation","tag-voltage-supplied-from-a-source-within-the-appliance-that-does-not-exceed-50-v-between-conductors-and-between-conductors-and-earth-or-functional-earth-when-the-appliance-is-supplied-at-rated-voltage","tag-single-insulation-applied-to-live-parts-that-provides-a-degree-of-protection-against-electric-shock-equivalent-to-double-insulation-under-the-conditions-specified-in-this-standard","tag-voltage-not-exceeding-42-v-between-conductors-and-between-conductors-and-earth-or-functional-earth-the-no-load-voltage-not-exceeding-50-v","tag-transformer-the-input-winding-of-which-is-electrically-separated-from-the-output-winding-by-an-insulation-at-least-equivalent-to-double-insulation-or-reinforced-insulation-that-is-intended-to-supply","tag-selv","tag-independent-insulation-applied-in-addition-to-basic-insulation-in-order-to-provide-protection-against-electric-shock-in-the-event-of-a-failure-of-basic-insulation"],"translation":{"provider":"WPGlobus","version":"3.0.1","language":"ro","enabled_languages":["en","es","ar","de","ja","fr","ru","th","nl","it","fa","ko","pt","hi","ro","tr","vi","id","zu"],"languages":{"en":{"title":true,"content":true,"excerpt":false},"es":{"title":true,"content":true,"excerpt":false},"ar":{"title":true,"content":true,"excerpt":false},"de":{"title":true,"content":true,"excerpt":false},"ja":{"title":true,"content":true,"excerpt":false},"fr":{"title":true,"content":true,"excerpt":false},"ru":{"title":true,"content":true,"excerpt":false},"th":{"title":true,"content":true,"excerpt":false},"nl":{"title":true,"content":true,"excerpt":false},"it":{"title":true,"content":true,"excerpt":false},"fa":{"title":false,"content":false,"excerpt":false},"ko":{"title":true,"content":true,"excerpt":false},"pt":{"title":true,"content":true,"excerpt":false},"hi":{"title":true,"content":true,"excerpt":false},"ro":{"title":true,"content":true,"excerpt":false},"tr":{"title":true,"content":true,"excerpt":false},"vi":{"title":true,"content":true,"excerpt":false},"id":{"title":true,"content":true,"excerpt":false},"zu":{"title":false,"content":false,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/posts\/2282","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/comments?post=2282"}],"version-history":[{"count":20,"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/posts\/2282\/revisions"}],"predecessor-version":[{"id":2355,"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/posts\/2282\/revisions\/2355"}],"wp:attachment":[{"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/media?parent=2282"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/categories?post=2282"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gezhi-tech.com\/ro\/wp-json\/wp\/v2\/tags?post=2282"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}