{"id":4275,"date":"2026-09-16T18:24:56","date_gmt":"2026-09-16T18:24:56","guid":{"rendered":"https:\/\/huyuglobal.com\/?p=4275"},"modified":"2026-09-16T18:26:33","modified_gmt":"2026-09-16T18:26:33","slug":"curve-breaker-definition","status":"publish","type":"post","link":"https:\/\/huyuglobal.com\/vi\/blog\/curve-breaker-definition\/","title":{"rendered":"\u0110\u1ecbnh ngh\u0129a Curve Breaker: \u00dd ngh\u0129a th\u1ef1c s\u1ef1 c\u1ee7a c\u00e1c Trip Curves B, C v\u00e0 D"},"content":{"rendered":"<p>B\u1ed9 ng\u1eaft m\u1ea1ch curve breaker c\u00f3 th\u1ec3 kh\u00f4ng ph\u1ea3i l\u00e0 m\u1ed9t lo\u1ea1i b\u1ed9 ng\u1eaft m\u1edbi nh\u01b0ng \u0111\u1ec1 c\u1eadp \u0111\u1ebfn b\u1ed9 ng\u1eaft c\u00f3 th\u1eddi gian ng\u1eaft \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edfi m\u1ed9t \u0111\u01b0\u1eddng cong \u0111\u00e3 \u0111\u01b0\u1ee3c thi\u1ebft l\u1eadp tr\u01b0\u1edbc sao cho n\u00f3 cho ph\u00e9p m\u1ea1ch ng\u1eaft m\u1ed7i khi m\u1ed9t \u0111\u1ed9ng c\u01a1 \u0111\u01b0\u1ee3c b\u1eadt ho\u1eb7c gi\u1eef \u0111\u00f3ng khi m\u1ed9t d\u00e2y d\u1eabn b\u1ecb ch\u00e1y. \u0110i\u1ec1u n\u00e0y d\u1ec5 b\u1ecb nh\u1ea7m l\u1eabn v\u00ec ti\u00eau \u0111\u1ec1 kh\u00f4ng li\u00ean quan \u0111\u1ebfn d\u00f2ng \u0111i\u1ec7n m\u00e0 li\u00ean quan \u0111\u1ebfn t\u1ed1c \u0111\u1ed9 ph\u1ea3n \u1ee9ng c\u1ee7a b\u1ed9 ng\u1eaft \u0111\u1ed1i v\u1edbi m\u1ed9t t\u1ef7 l\u1ec7 nh\u1ea5t \u0111\u1ecbnh c\u1ee7a d\u00f2ng \u0111\u1ecbnh m\u1ee9c c\u1ee7a n\u00f3. V\u00ec v\u1eady, b\u1ea5t k\u1ec3 gi\u00e1 tr\u1ecb ampe l\u00e0 bao nhi\u00eau, vi\u1ec7c ph\u00e1 v\u1ee1 \u0111\u01b0\u1eddng cong sai s\u1ebd c\u00f3 ngh\u0129a l\u00e0 kh\u00f4ng c\u00f3 gi\u1ea3i ph\u00e1p cho v\u1ea5n \u0111\u1ec1, \u0111\u00f3 l\u00e0 l\u00fd do t\u1ea1i sao c\u00f9ng m\u1ed9t l\u1ea7n ng\u1eaft phi\u1ec1n ph\u1ee9c khi\u1ebfn k\u1ef9 s\u01b0 t\u00ecm ki\u1ebfm b\u1ed9 ng\u1eaft l\u1edbn h\u01a1n c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft ch\u1ec9 khi m\u1ed9t ch\u1eef c\u00e1i trong t\u00ean c\u1ee7a n\u00f3 \u0111\u01b0\u1ee3c thay \u0111\u1ed5i. H\u01b0\u1edbng d\u1eabn n\u00e0y cung c\u1ea5p \u0111\u1ecbnh ngh\u0129a v\u1ec1 \u0111\u01b0\u1eddng cong ng\u1eaft, m\u00f4 t\u1ea3 c\u00e1c \u0111\u01b0\u1eddng cong v\u00e0 m\u1ee9c ng\u1eaft, c\u0169ng nh\u01b0 gi\u1ea3i th\u00edch t\u1ea1i sao c\u1ea7n ph\u1ea3i ch\u1ecdn ch\u00fang m\u1ed9t c\u00e1ch ch\u00ednh x\u00e1c.<\/p>\n<blockquote><p>T\u00f3m l\u1ea1i, curve breaker l\u00e0 m\u1ed9t lo\u1ea1i b\u1ed9 ng\u1eaft m\u1ea1ch c\u1ee5 th\u1ec3 s\u1eed d\u1ee5ng c\u00e1c \u0111\u01b0\u1eddng cong ti\u00eau chu\u1ea9n (\u0111\u01b0\u1ee3c g\u00e1n nh\u00e3n B, C ho\u1eb7c D); m\u1ed7i \u0111\u01b0\u1eddng cong hi\u1ec3n th\u1ecb \u0111\u1eb7c t\u00ednh ng\u1eaft th\u1eddi gian-d\u00f2ng \u0111i\u1ec7n, cho bi\u1ebft c\u00e0i \u0111\u1eb7t c\u1ee7a van ng\u1eaft t\u1eeb t\u00ednh. C\u00e1c lo\u1ea1i b\u1ed9 ng\u1eaft m\u1ea1ch kh\u00e1c nhau c\u00f3 c\u00e1c c\u00e0i \u0111\u1eb7t ng\u1eaft kh\u00e1c nhau d\u1ef1a tr\u00ean d\u00f2ng In. D\u00f2ng ng\u1eaft c\u1ee7a curve breaker \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a trong b\u1ea3ng d\u01b0\u1edbi \u0111\u00e2y, trong \u0111\u00f3 b\u1ed9 ng\u1eaft lo\u1ea1i B n\u00ean ng\u1eaft \u1edf m\u1ee9c 3 \u0111\u1ebfn 5 l\u1ea7n In, lo\u1ea1i C \u1edf m\u1ee9c 5 \u0111\u1ebfn 10 l\u1ea7n In, v\u00e0 lo\u1ea1i D \u1edf m\u1ee9c 10 \u0111\u1ebfn 20 l\u1ea7n In, theo ti\u00eau chu\u1ea9n IEC\/EN 60898-1. \u0110\u1eb7c t\u00ednh nhi\u1ec7t l\u00e0 gi\u1ed1ng nhau cho c\u1ea3 3 lo\u1ea1i b\u1ed9 ng\u1eaft; tuy nhi\u00ean, d\u00f2ng ng\u1eaft t\u1ee9c th\u1eddi th\u00ec kh\u00e1c nhau. Do \u0111\u00f3, v\u00ed d\u1ee5, b\u1ed9 ng\u1eaft lo\u1ea1i B c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng v\u1edbi t\u1ea3i \u0111i\u1ec7n t\u1eed c\u00f3 d\u00f2ng kh\u1edfi \u0111\u1ed9ng th\u1ea5p, b\u1ed9 ng\u1eaft lo\u1ea1i C c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng v\u1edbi c\u00e1c t\u1ea3i h\u1ed7n h\u1ee3p v\u00e0 \u0111\u1ed9ng c\u01a1 th\u00f4ng th\u01b0\u1eddng, v\u00e0 cu\u1ed1i c\u00f9ng b\u1ed9 ng\u1eaft lo\u1ea1i D d\u00e0nh cho thi\u1ebft b\u1ecb c\u00f3 d\u00f2ng kh\u1edfi \u0111\u1ed9ng l\u1edbn.<\/p><\/blockquote>\n<h2>\u00dd ngh\u0129a c\u1ee7a \u201cCurve Breaker\u201d<\/h2>\n<p>C\u1ee5m t\u1eeb n\u00e0y m\u00f4 t\u1ea3 m\u1ed9t lo\u1ea1i b\u1ed9 ng\u1eaft m\u1ea1ch ho\u1ea1t \u0111\u1ed9ng theo \u0111\u1eb7c t\u00ednh th\u1eddi gian-d\u00f2ng \u0111i\u1ec7n \u0111\u00e3 \u0111\u01b0\u1ee3c thi\u1ebft l\u1eadp tr\u01b0\u1edbc thay v\u00ec m\u1ed9t \u0111i\u1ec3m th\u1eddi gian duy nh\u1ea5t khi n\u00f3 ng\u1eaft c\u00f4ng t\u1eafc. M\u1ed7i b\u1ed9 ng\u1eaft m\u1ea1ch nhi\u1ec7t t\u1eeb lo\u1ea1i nh\u1ecf c\u00f3 \u201c\u0111\u01b0\u1eddng cong\u201d ri\u00eang c\u1ee7a n\u00f3. \u201c\u0110\u01b0\u1eddng cong\u201d l\u00e0 t\u00ean g\u1ecdi c\u1ee7a thu\u1eadt ng\u1eef \u0111\u1ecbnh ngh\u0129a c\u00e1ch thi\u1ebft b\u1ecb n\u00e0y ho\u1ea1t \u0111\u1ed9ng khi ch\u1ecbu c\u00e1c d\u00f2ng \u0111i\u1ec7n kh\u00e1c nhau.<\/p>\n<p>C\u00f3 hai c\u01a1 ch\u1ebf ch\u1ecbu tr\u00e1ch nhi\u1ec7m cho qu\u00e1 tr\u00ecnh n\u00e0y. C\u01a1 ch\u1ebf \u0111\u1ea7u ti\u00ean l\u00e0 thi\u1ebft b\u1ecb nhi\u1ec7t \u2013 m\u1ed9t d\u1ea3i kim lo\u1ea1i k\u00e9p \u0111\u01b0\u1ee3c l\u00e0m n\u00f3ng b\u1edfi d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua n\u00f3. N\u1ebfu x\u1ea3y ra qu\u00e1 t\u1ea3i, d\u1ea3i kim lo\u1ea1i s\u1ebd u\u1ed1n cong d\u1ea7n cho \u0111\u1ebfn khi n\u00f3 ng\u1eaft; do \u0111\u00f3, n\u00f3 v\u1eeba c\u00f3 \u00fd ngh\u0129a b\u1ea3o v\u1ec7 ch\u1ed1ng qu\u00e1 nhi\u1ec7t ch\u1eadm c\u1ee7a d\u00e2y d\u1eabn v\u00e0 ho\u1ea1t \u0111\u1ed9ng theo m\u1ed9t \u0111\u01b0\u1eddng cong g\u1ecdi l\u00e0 \u0111\u01b0\u1eddng cong ngh\u1ecbch th\u1eddi gian v\u00ec n\u00f3 nhanh h\u01a1n khi qu\u00e1 t\u1ea3i t\u0103ng l\u00ean, m\u1eb7c d\u00f9 kh\u00f4ng ph\u1ea3i ngay l\u1eadp t\u1ee9c. C\u01a1 ch\u1ebf th\u1ee9 hai l\u00e0 thi\u1ebft b\u1ecb t\u1eeb t\u00ednh, ho\u1eb7c solenoid, t\u0103ng l\u1ef1c t\u00e1c \u0111\u1ed9ng l\u00ean m\u1ea1ch khi d\u00f2ng \u0111i\u1ec7n t\u0103ng l\u00ean. \u0110\u00e2y l\u00e0 c\u00e1ch ph\u1ea7n t\u1ee9c th\u1eddi c\u1ee7a \u0111\u01b0\u1eddng cong \u0111\u01b0\u1ee3c t\u1ea1o ra.<\/p>\n<p>V\u00ec c\u1ea3 hai c\u01a1 ch\u1ebf \u0111\u1ec1u \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho c\u00f9ng m\u1ed9t c\u01a1 ch\u1ebf ti\u1ebfp \u0111i\u1ec3m, \u201c\u0111\u01b0\u1eddng cong\u201d \u0111\u1ea1i di\u1ec7n cho c\u00e1ch hai c\u01a1 ch\u1ebf n\u00e0y ho\u1ea1t \u0111\u1ed9ng c\u00f9ng nhau: \u0111\u1ed9 d\u1ed1c ngh\u1ecbch \u0111\u1ea3o m\u01b0\u1ee3t m\u00e0 \u1edf gi\u00e1 tr\u1ecb d\u00f2ng \u0111i\u1ec7n th\u1ea5p n\u01a1i thi\u1ebft b\u1ecb nhi\u1ec7t ho\u1ea1t \u0111\u1ed9ng v\u00e0 s\u1ef1 gi\u1ea3m g\u1ea7n nh\u01b0 th\u1eb3ng \u0111\u1ee9ng trong ph\u1ea7n n\u00e0y c\u1ee7a \u0111\u01b0\u1eddng cong khi thi\u1ebft b\u1ecb t\u1eeb t\u00ednh ki\u1ec3m so\u00e1t. \u0110i\u1ec3m m\u00e0 \u0111\u01b0\u1eddng cong chuy\u1ec3n sang th\u1eb3ng \u0111\u1ee9ng l\u00e0 gi\u00e1 tr\u1ecb \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edfi ch\u1eef c\u00e1i c\u1ee7a n\u00f3. C\u00e1c thi\u1ebft b\u1ecb \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng theo nguy\u00ean t\u1eafc n\u00e0y, v\u00e0 c\u00e1c h\u1ecd m\u00e0 ch\u00fang thu\u1ed9c v\u1ec1, \u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp trong h\u01b0\u1edbng d\u1eabn c\u1ee7a ch\u00fang t\u00f4i v\u1ec1 <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/what-is-mccb-and-mcb\/\">L\u1ef1a ch\u1ecdn MCB v\u00e0 MCCB<\/a>.<\/p>\n<p>\u00dd ngh\u0129a th\u1ef1c t\u1ebf l\u00e0 \u0111\u01b0\u1eddng cong kh\u00f4ng \u0111\u1ea1i di\u1ec7n cho ch\u1ea5t l\u01b0\u1ee3ng ho\u1eb7c \u0111\u1ecbnh m\u1ee9c d\u00f2ng \u0111i\u1ec7n. C\u1ea3 b\u1ed9 ng\u1eaft m\u1ea1ch lo\u1ea1i B 20A v\u00e0 b\u1ed9 ng\u1eaft m\u1ea1ch lo\u1ea1i D 20A \u0111\u1ec1u mang d\u00f2ng 20A li\u00ean t\u1ee5c v\u00e0 b\u1ea3o v\u1ec7 m\u1ea1ch 20A. S\u1ef1 kh\u00e1c bi\u1ec7t duy nh\u1ea5t gi\u1eefa hai b\u1ed9 ng\u1eaft m\u1ea1ch l\u00e0 m\u1ee9c d\u00f2ng \u0111i\u1ec7n m\u00e0 ch\u00fang c\u00f3 th\u1ec3 ch\u1ecbu \u0111\u01b0\u1ee3c trong th\u1eddi gian ng\u1eafn.<\/p>\n<h2>C\u1ea5u t\u1ea1o c\u1ee7a \u0110\u01b0\u1eddng cong ng\u1eaft m\u1ea1ch<\/h2>\n<p>\u0110\u01b0\u1eddng cong ng\u1eaft m\u1ea1ch \u0111\u01b0\u1ee3c bi\u1ec3u di\u1ec5n b\u1eb1ng tr\u1ee5c log-log. Tr\u1ee5c ngang l\u00e0 d\u00f2ng \u0111i\u1ec7n d\u01b0\u1edbi d\u1ea1ng t\u1ef7 l\u1ec7 c\u1ee7a d\u00f2ng \u0111\u1ecbnh m\u1ee9c; t\u1ee9c l\u00e0, I\/In. Tr\u1ee5c d\u1ecdc l\u00e0 th\u1eddi gian ng\u1eaft m\u1ea1ch, \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ecb b\u1eb1ng gi\u00e2y t\u1eeb h\u00e0ng ngh\u00ecn gi\u00e2y \u0111\u1ebfn mili gi\u00e2y.<\/p>\n<table>\n<tbody>\n<tr>\n<th>V\u00f9ng c\u1ee7a \u0111\u01b0\u1eddng cong<\/th>\n<th>Ph\u1ea1m vi d\u00f2ng \u0111i\u1ec7n<\/th>\n<th>C\u01a1 ch\u1ebf<\/th>\n<th>B\u1ea3o v\u1ec7 ch\u1ed1ng l\u1ea1i \u0111i\u1ec1u g\u00ec<\/th>\n<\/tr>\n<tr>\n<td>V\u00f9ng kh\u00f4ng ng\u1eaft m\u1ea1ch<\/td>\n<td>L\u00ean \u0111\u1ebfn kho\u1ea3ng 1,13 \u00d7 I<sub>n<\/sub><\/td>\n<td>Kh\u00f4ng c\u00f3 ph\u1ea7n t\u1eed n\u00e0o ho\u1ea1t \u0111\u1ed9ng<\/td>\n<td>\u2014 d\u00f2ng t\u1ea3i b\u00ecnh th\u01b0\u1eddng<\/td>\n<\/tr>\n<tr>\n<td>D\u1ea3i nhi\u1ec7t kh\u00f4ng x\u00e1c \u0111\u1ecbnh<\/td>\n<td>1,13-1,45 \u00d7 I<sub>n<\/sub><\/td>\n<td>Nhi\u1ec7t; c\u00f3 th\u1ec3 ho\u1eb7c kh\u00f4ng ng\u1eaft trong th\u1eddi gian quy \u0111\u1ecbnh<\/td>\n<td>Qu\u00e1 t\u1ea3i bi\u00ean<\/td>\n<\/tr>\n<tr>\n<td>Ng\u1eaft nhi\u1ec7t ch\u1eafc ch\u1eafn<\/td>\n<td>Tr\u00ean 1,45 \u00d7 I<sub>n<\/sub><\/td>\n<td>Nhi\u1ec7t, th\u1eddi gian ngh\u1ecbch \u0111\u1ea3o<\/td>\n<td>Qu\u00e1 t\u1ea3i v\u00e0 qu\u00e1 nhi\u1ec7t c\u00e1p<\/td>\n<\/tr>\n<tr>\n<td>Chuy\u1ec3n ti\u1ebfp t\u1eeb t\u00ednh<\/td>\n<td>3-5\u00d7 (B), 5-10\u00d7 (C), 10-20\u00d7 (D)<\/td>\n<td>T\u1eeb t\u00ednh, t\u1ee9c th\u1eddi<\/td>\n<td>Ph\u00e2n bi\u1ec7t ng\u1eafn m\u1ea1ch v\u00e0 d\u00f2ng kh\u1edfi \u0111\u1ed9ng cao<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Thay v\u00ec xem d\u1eef li\u1ec7u trong b\u1ea3ng theo kh\u00eda c\u1ea1nh an to\u00e0n, ch\u00fang n\u00ean \u0111\u01b0\u1ee3c xem nh\u01b0 m\u1ed9t c\u00e2u chuy\u1ec7n v\u1ec1 s\u1ef1 ph\u00e2n bi\u1ec7t. V\u00f9ng nhi\u1ec7t l\u00e0 gi\u1ed1ng h\u1ec7t nhau cho m\u1ed7i \u0111\u01b0\u1eddng cong v\u00ec b\u1ea3o v\u1ec7 c\u00e1p l\u00e0 v\u1ea5n \u0111\u1ec1 chung b\u1ea5t k\u1ec3 lo\u1ea1i t\u1ea3i. Ch\u00ednh trong v\u00f9ng t\u1eeb t\u00ednh m\u00e0 nh\u00e0 s\u1ea3n xu\u1ea5t quy\u1ebft \u0111\u1ecbnh thi\u1ebft b\u1ecb c\u00f3 n\u00ean ng\u1eaft khi d\u00f2ng \u0111i\u1ec7n th\u1ea5p theo c\u00e1ch b\u1ea3o v\u1ec7 thi\u1ebft b\u1ecb nh\u1ea1y c\u1ea3m nh\u01b0ng b\u1ecf qua t\u1ea5t c\u1ea3 c\u00e1c d\u00f2ng kh\u1edfi \u0111\u1ed9ng ch\u1ea5p nh\u1eadn \u0111\u01b0\u1ee3c hay ng\u01b0\u1ee3c l\u1ea1i \u2013 ng\u1eaft mu\u1ed9n cho ph\u00e9p t\u1ea5t c\u1ea3 c\u00e1c d\u00f2ng kh\u1edfi \u0111\u1ed9ng \u0111\u01b0\u1ee3c ch\u1ea5p nh\u1eadn v\u1edbi vi\u1ec7c thi\u1ebft b\u1ecb s\u1ebd ph\u1ea3n \u1ee9ng ch\u1eadm h\u01a1n v\u1edbi c\u00e1c l\u1ed7i qu\u00e1 d\u00f2ng th\u1ef1c s\u1ef1. Ch\u1eef c\u00e1i c\u1ee7a \u0111\u01b0\u1eddng cong l\u00e0 ghi nh\u1eadn c\u1ee7a l\u1ef1a ch\u1ecdn n\u00e0y.<\/p>\n<p>M\u1ed9t \u0111i\u1ec3m quan tr\u1ecdng c\u1ea7n \u0111\u01b0\u1ee3c l\u00e0m r\u00f5 v\u00ec n\u00f3 cho th\u1ea5y t\u00ednh th\u1ef1c ti\u1ec5n c\u1ee7a to\u00e0n b\u1ed9 v\u1ea5n \u0111\u1ec1 l\u1ef1a ch\u1ecdn \u0111\u01b0\u1eddng cong. D\u00f2ng kh\u1edfi \u0111\u1ed9ng l\u00e0 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng th\u1ef1c t\u1ebf v\u00e0 kh\u00e1 b\u00ecnh th\u01b0\u1eddng. M\u1ed9t \u0111\u1ed9ng c\u01a1 c\u1ea3m \u1ee9ng AC th\u00f4ng th\u01b0\u1eddng l\u1ea5y t\u1eeb n\u0103m \u0111\u1ebfn t\u00e1m l\u1ea7n d\u00f2ng \u0111\u1ecbnh m\u1ee9c trong m\u1ed9t kho\u1ea3ng th\u1eddi gian r\u1ea5t ng\u1eafn ngay sau khi kh\u1edfi \u0111\u1ed9ng. M\u1ed9t m\u00e1y bi\u1ebfn \u00e1p khi k\u1ebft n\u1ed1i v\u00e0o l\u01b0\u1edbi c\u00f3 th\u1ec3 ti\u00eau th\u1ee5 t\u1eeb m\u01b0\u1eddi \u0111\u1ebfn m\u01b0\u1eddi b\u1ed1n l\u1ea7n d\u00f2ng \u0111\u1ecbnh m\u1ee9c trong c\u00e1c chu k\u1ef3 \u0111\u1ea7u ti\u00ean. N\u1ebfu gi\u00e1 tr\u1ecb d\u00f2ng \u0111i\u1ec7n th\u1ea5p h\u01a1n b\u1ea5t k\u1ef3 gi\u00e1 tr\u1ecb n\u00e0o trong s\u1ed1 \u0111\u00f3 th\u00ec thi\u1ebft b\u1ecb s\u1ebd ng\u1eaft m\u1ed7i l\u1ea7n ngay c\u1ea3 khi kh\u00f4ng c\u00f3 l\u1ed7i. C\u00f9ng m\u1ed9t logic n\u00ean \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng cho c\u00e1c ti\u1ebfp \u0111i\u1ec3m \u0111i\u1ec1u khi\u1ec3n c\u00f9ng v\u1edbi c\u00e1c thi\u1ebft b\u1ecb b\u1ea3o v\u1ec7, v\u00ec ch\u00fang th\u1ef1c hi\u1ec7n vi\u1ec7c chuy\u1ec3n m\u1ea1ch nh\u01b0ng kh\u00f4ng lo\u1ea1i b\u1ecf l\u1ed7i.<\/p>\n<h2>C\u00e1c \u0110\u01b0\u1eddng cong Ti\u00eau chu\u1ea9n<\/h2>\n<p>IEC\/EN 60898-1 \u0111\u1ecbnh ngh\u0129a ba \u0111\u01b0\u1eddng cong \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong ph\u1ea7n l\u1edbn c\u00e1c l\u1eafp \u0111\u1eb7t d\u00e2n d\u1ee5ng v\u00e0 th\u01b0\u01a1ng m\u1ea1i nh\u1eb9.<\/p>\n<table>\n<tbody>\n<tr>\n<th>\u0110\u01b0\u1eddng cong<\/th>\n<th>Ng\u01b0\u1ee1ng ng\u1eaft t\u1eeb t\u00ednh<\/th>\n<th>Th\u1eddi gian ng\u1eaft \u0111i\u1ec3n h\u00ecnh t\u1ea1i ng\u01b0\u1ee1ng<\/th>\n<th>Thi\u1ebft k\u1ebf cho<\/th>\n<th>C\u00e1c m\u1ea1ch cu\u1ed1i trong nh\u00e0 v\u00e0 c\u00e1c t\u00f2a nh\u00e0 th\u01b0\u01a1ng m\u1ea1i: chi\u1ebfu s\u00e1ng, \u1ed5 c\u1eafm, thi\u1ebft b\u1ecb nh\u1ecf<\/th>\n<\/tr>\n<tr>\n<td><strong>Lo\u1ea1i B<\/strong><\/td>\n<td>3-5 \u00d7 I<sub>n<\/sub><\/td>\n<td>0,1 gi\u00e2y tr\u1edf xu\u1ed1ng \u1edf \u0111\u1ea7u tr\u00ean<\/td>\n<td>T\u1ea3i c\u00f3 d\u00f2ng kh\u1edfi \u0111\u1ed9ng t\u1ed1i thi\u1ec3u<\/td>\n<td>M\u1ea1ch chi\u1ebfu s\u00e1ng, s\u01b0\u1edfi \u0111i\u1ec7n tr\u1edf, \u1ed5 c\u1eafm trong c\u00f4ng vi\u1ec7c d\u00e2n d\u1ee5ng, ngu\u1ed3n PLC v\u00e0 thi\u1ebft b\u1ecb \u0111o l\u01b0\u1eddng, m\u1ea1ch \u0111i\u1ec1u khi\u1ec3n<\/td>\n<\/tr>\n<tr>\n<td><strong>Lo\u1ea1i C<\/strong><\/td>\n<td>5-10 \u00d7 I<sub>n<\/sub><\/td>\n<td>0,1 gi\u00e2y tr\u1edf xu\u1ed1ng \u1edf \u0111\u1ea7u tr\u00ean<\/td>\n<td>T\u1ea3i c\u1ea3m \u1ee9ng v\u00e0 t\u1ea3i h\u1ed7n h\u1ee3p<\/td>\n<td>\u0110\u1ed9ng c\u01a1 ti\u00eau chu\u1ea9n, b\u01a1m, qu\u1ea1t, HVAC, m\u1ea1ch \u1ed5 c\u1eafm th\u01b0\u01a1ng m\u1ea1i, ph\u00e2n ph\u1ed1i c\u00f4ng nghi\u1ec7p chung<\/td>\n<\/tr>\n<tr>\n<td><strong>Lo\u1ea1i D<\/strong><\/td>\n<td>10-20 \u00d7 I<sub>n<\/sub><\/td>\n<td>0,1 gi\u00e2y tr\u1edf xu\u1ed1ng \u1edf \u0111\u1ea7u tr\u00ean<\/td>\n<td>D\u00f2ng kh\u1edfi \u0111\u1ed9ng r\u1ea5t cao<\/td>\n<td>M\u00e1y bi\u1ebfn \u00e1p l\u1edbn, m\u00e1y h\u00e0n, thi\u1ebft b\u1ecb X-ray, m\u00e1y ph\u00e1t \u0111i\u1ec7n, \u0111\u1ed9ng c\u01a1 l\u1edbn, c\u1ea7n c\u1ea9u v\u00e0 thang m\u00e1y, m\u00e1y n\u00e9n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4276\" src=\"https:\/\/huyuglobal.com\/wp-content\/uploads\/2026\/09\/The-Standard-Curves.webp\" alt=\"C\u00e1c \u0110\u01b0\u1eddng cong Ti\u00eau chu\u1ea9n\" width=\"1448\" height=\"1086\" \/><\/p>\n<p>M\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3 \u0111\u1ec3 theo d\u00f5i th\u1ee9 b\u1eadc l\u00e0 c\u00e1c ph\u1ea1m vi s\u1ed1 th\u01b0\u1eddng c\u00f3 xu h\u01b0\u1edbng li\u00ean ti\u1ebfp, ngh\u0129a l\u00e0 c\u00e1c \u0111\u01b0\u1eddng cong gi\u1ed1ng nh\u01b0 m\u1ed9t chu\u1ed7i c\u00e1c b\u1eadc trong \u0111\u1ed9 dung sai. \u1ede B, s\u1ed1 l\u1ea7n c\u00f3 th\u1ec3 v\u01b0\u1ee3t m\u1ee9c \u0111\u1ecbnh m\u1ee9c kho\u1ea3ng t\u1eeb ba \u0111\u1ebfn n\u0103m, trong khi \u1edf C con s\u1ed1 n\u00e0y dao \u0111\u1ed9ng t\u1eeb n\u0103m \u0111\u1ebfn m\u01b0\u1eddi v\u00e0 \u1edf D t\u1eeb m\u01b0\u1eddi \u0111\u1ebfn hai m\u01b0\u01a1i. Tr\u00ean ng\u01b0\u1ee1ng, m\u1ecdi th\u1ee9 ph\u1ea3n \u1ee9ng g\u1ea7n nh\u01b0 ngay l\u1eadp t\u1ee9c, d\u01b0\u1edbi ng\u01b0\u1ee1ng th\u00ec m\u1ecdi th\u1ee9 ph\u1ea3i \u0111\u01b0\u1ee3c x\u1eed l\u00fd qua t\u00e1c nh\u00e2n nhi\u1ec7t ch\u1eadm h\u01a1n n\u1ebfu c\u00f3 th\u1ec3 x\u1eed l\u00fd \u0111\u01b0\u1ee3c.<\/p>\n<p>C\u00f3 hai \u0111i\u1ec3m li\u00ean quan \u0111\u1ebfn Lo\u1ea1i C \u0111\u00e1ng ch\u00fa \u00fd. Th\u1ee9 nh\u1ea5t, Lo\u1ea1i C th\u1ef1c s\u1ef1 l\u00e0 l\u1ef1a ch\u1ecdn m\u1eb7c \u0111\u1ecbnh cho h\u1ea7u h\u1ebft thi\u1ebft b\u1ecb th\u01b0\u01a1ng m\u1ea1i v\u00e0 s\u1ea3n xu\u1ea5t trong ng\u00e0nh v\u00ec n\u00f3 \u0111\u1ee7 t\u1ed1t v\u1ec1 c\u00e2n b\u1eb1ng gi\u1eefa m\u1ee9c dung sai d\u00f2ng kh\u1edfi \u0111\u1ed9ng v\u00e0 m\u1ee9c nh\u1ea1y c\u1ea3m l\u1ed7i. Th\u00eam v\u00e0o \u0111\u00f3, n\u00f3 kh\u00f4ng ph\u1ea3i l\u00e0 l\u1ef1a ch\u1ecdn t\u1ed3i cho t\u1ea3i \u0111i\u1ec7n tr\u1edf v\u00ec v\u1eabn ho\u1ea1t \u0111\u1ed9ng t\u1ed1t trong b\u1ea3o v\u1ec7 c\u00e1p. L\u00fd do ch\u00ednh \u0111\u1ec3 s\u1eed d\u1ee5ng Lo\u1ea1i B l\u00e0 y\u1ebfu t\u1ed1 nh\u1ea1y c\u1ea3m: n\u00f3 s\u1ebd ng\u1eaft khi c\u00f3 nhi\u1ec5u t\u1eeb t\u00ednh th\u1ea5p h\u01a1n v\u00e0 do \u0111\u00f3 c\u00f3 kh\u1ea3 n\u0103ng \u0111\u1ec3 l\u1ed7i ph\u00e1t tri\u1ec3n v\u00e0 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn m\u1ea1ch \u0111i\u1ec1u khi\u1ec3n \u0111\u1eaft ti\u1ec1n tr\u01b0\u1edbc khi thi\u1ebft b\u1ecb Lo\u1ea1i B \u0111\u01b0\u1ee3c k\u00edch ho\u1ea1t.<\/p>\n<h2>C\u00e1c \u0110\u01b0\u1eddng Cong v\u00e0 Bi\u1ebfn Th\u1ec3 Kh\u00e1c<\/h2>\n<p>B, C v\u00e0 D l\u00e0 b\u1ed9 ti\u00eau chu\u1ea9n, nh\u01b0ng c\u00f2n t\u1ed3n t\u1ea1i m\u1ed9t s\u1ed1 \u0111\u1eb7c t\u00ednh kh\u00e1c cho c\u00e1c v\u1ea5n \u0111\u1ec1 c\u1ee5 th\u1ec3.<\/p>\n<table>\n<tbody>\n<tr>\n<th>\u0110\u01b0\u1eddng cong<\/th>\n<th>Ng\u01b0\u1ee1ng t\u1eeb t\u00ednh<\/th>\n<th>M\u1ee5c \u0111\u00edch s\u1eed d\u1ee5ng<\/th>\n<\/tr>\n<tr>\n<td>Lo\u1ea1i A<\/td>\n<td>2-3 \u00d7 I<sub>n<\/sub><\/td>\n<td>T\u1ea3i b\u00e1n d\u1eabn v\u00e0 \u0111i\u1ec7n t\u1eed y\u00eau c\u1ea7u b\u1ea3o v\u1ec7 ng\u1eafn m\u1ea1ch r\u1ea5t nh\u1ea1y; ng\u1eafn m\u1ea1ch tr\u00ean c\u00e1c \u0111o\u1ea1n c\u00e1p d\u00e0i<\/td>\n<\/tr>\n<tr>\n<td>Lo\u1ea1i Z<\/td>\n<td>2-3 \u00d7 I<sub>n<\/sub><\/td>\n<td>M\u1ea1ch \u0111i\u1ec7n t\u1eed v\u00e0 \u0111i\u1ec1u khi\u1ec3n \u01b0u ti\u00ean \u0111\u1ed9 nh\u1ea1y; t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi Lo\u1ea1i A nh\u01b0ng c\u00f3 ngu\u1ed3n g\u1ed1c ti\u00eau chu\u1ea9n kh\u00e1c<\/td>\n<\/tr>\n<tr>\n<td>Lo\u1ea1i K<\/td>\n<td>8-12 \u00d7 I<sub>n<\/sub><\/td>\n<td>\u0110\u1ed9ng c\u01a1, m\u00e1y bi\u1ebfn \u00e1p v\u00e0 thi\u1ebft b\u1ecb c\u00f3 d\u00f2ng kh\u1edfi \u0111\u1ed9ng cao m\u00e0 Lo\u1ea1i D s\u1ebd qu\u00e1 k\u00e9m nh\u1ea1y<\/td>\n<\/tr>\n<tr>\n<td>Lo\u1ea1i MA<\/td>\n<td>Ch\u1ec9 t\u1eeb t\u00ednh, kho\u1ea3ng 12 \u00d7 I<sub>n<\/sub><\/td>\n<td>B\u1ea3o v\u1ec7 m\u1ea1ch \u0111\u1ed9ng c\u01a1 n\u01a1i qu\u00e1 t\u1ea3i \u0111\u01b0\u1ee3c x\u1eed l\u00fd b\u1edfi r\u01a1le qu\u00e1 t\u1ea3i ri\u00eang bi\u1ec7t; kh\u00f4ng c\u00f3 ph\u1ea7n t\u1eed nhi\u1ec7t<\/td>\n<\/tr>\n<tr>\n<td>\u0110\u01b0\u1eddng cong \u0111i\u1ec1u ch\u1ec9nh \u0111\u01b0\u1ee3c (MCCB)<\/td>\n<td>\u0110i\u1ec1u ch\u1ec9nh t\u1ea1i hi\u1ec7n tr\u01b0\u1eddng<\/td>\n<td>B\u1ed9 ng\u1eaft m\u1ea1ch v\u1ecf \u0111\u00fac n\u01a1i \u0111\u01b0\u1eddng cong v\u00e0 \u0111\u1ecbnh m\u1ee9c \u0111\u01b0\u1ee3c thi\u1ebft l\u1eadp theo l\u1eafp \u0111\u1eb7t v\u00e0 c\u00f3 th\u1ec3 ph\u1ed1i h\u1ee3p v\u1edbi thi\u1ebft b\u1ecb ph\u00eda tr\u00ean<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>S\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa c\u00e1c d\u00f2ng thi\u1ebft b\u1ecb quan tr\u1ecdng v\u00ec c\u00e1c \u0111\u01b0\u1eddng cong c\u00f3 s\u1eb5n s\u1ebd ph\u1ee5 thu\u1ed9c v\u00e0o ti\u00eau chu\u1ea9n s\u1eed d\u1ee5ng \u0111\u1ec3 s\u1ea3n xu\u1ea5t b\u1ed9 ng\u1eaft m\u1ea1ch. B\u1ed9 ng\u1eaft m\u1ea1ch nh\u1ecf tu\u00e2n th\u1ee7 IEC 60898-1 s\u1eed d\u1ee5ng \u0111\u01b0\u1eddng cong c\u1ed1 \u0111\u1ecbnh kh\u00f4ng th\u1ec3 \u0111i\u1ec1u ch\u1ec9nh trong c\u00e1c d\u00f2ng B, C ho\u1eb7c D. Trong khi \u0111\u00f3, b\u1ed9 ng\u1eaft m\u1ea1ch v\u1ecf \u0111\u00fac tu\u00e2n th\u1ee7 IEC 60947-2 th\u01b0\u1eddng c\u00f3 kh\u1ea3 n\u0103ng \u0111i\u1ec1u ch\u1ec9nh m\u1ed9t s\u1ed1 thi\u1ebft l\u1eadp t\u1eeb t\u00ednh v\u00e0 nhi\u1ec7t, t\u1ea1o \u0111i\u1ec1u ki\u1ec7n \u0111\u1ed3ng b\u1ed9 h\u00f3a to\u00e0n h\u1ec7 th\u1ed1ng ph\u00e2n ph\u1ed1i thay v\u00ec c\u00e1c t\u00f9y ch\u1ecdn c\u1ed1 \u0111\u1ecbnh. Quy\u1ebft \u0111\u1ecbnh gi\u1eefa c\u00e1c d\u00f2ng thi\u1ebft b\u1ecb li\u00ean quan \u0111\u1ebfn \u0111\u1ecbnh m\u1ee9c, m\u1ee9c l\u1ed7i v\u00e0 \u0111i\u1ec1u ch\u1ec9nh ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u1ef1a ch\u1ecdn \u0111\u01b0\u1eddng cong.<\/p>\n<h2>\u0110\u01b0\u1eddng cong B so v\u1edbi \u0111\u01b0\u1eddng cong C<\/h2>\n<p>\u0110\u00e2y l\u00e0 so s\u00e1nh th\u1ef1c t\u1ebf ph\u1ed5 bi\u1ebfn nh\u1ea5t, v\u00e0 c\u00e2u tr\u1ea3 l\u1eddi g\u1ea7n nh\u01b0 ho\u00e0n to\u00e0n d\u1ef1a tr\u00ean d\u00f2ng kh\u1edfi \u0111\u1ed9ng.<\/p>\n<table>\n<tbody>\n<tr>\n<th><\/th>\n<th>Lo\u1ea1i B<\/th>\n<th>Lo\u1ea1i C<\/th>\n<\/tr>\n<tr>\n<td>D\u1ea3i ng\u1eaft t\u1eeb t\u00ednh<\/td>\n<td>3-5 \u00d7 I<sub>n<\/sub><\/td>\n<td>5-10 \u00d7 I<sub>n<\/sub><\/td>\n<\/tr>\n<tr>\n<td>Ph\u1ea3n \u1ee9ng v\u1edbi d\u00f2ng 6 \u00d7 I<sub>n<\/sub> t\u0103ng \u0111\u1ed9t bi\u1ebfn<\/td>\n<td>Ng\u1eaft ngay l\u1eadp t\u1ee9c \u1edf ph\u1ea7n tr\u00ean c\u1ee7a d\u1ea3i<\/td>\n<td>C\u00f3 th\u1ec3 ch\u1ecbu \u0111\u01b0\u1ee3c; ch\u1ec9 ng\u1eaft tr\u00ean 5 \u00d7 t\u00f9y thi\u1ebft b\u1ecb c\u1ee5 th\u1ec3<\/td>\n<\/tr>\n<tr>\n<td>\u0110\u1ed9 nh\u1ea1y v\u1edbi l\u1ed7i th\u1ef1c s\u1ef1<\/td>\n<td>Cao h\u01a1n \u2014 ph\u00e1t hi\u1ec7n ng\u1eafn m\u1ea1ch c\u00f3 c\u01b0\u1eddng \u0111\u1ed9 th\u1ea5p h\u01a1n<\/td>\n<td>Th\u1ea5p h\u01a1n \u2014 ng\u1eafn m\u1ea1ch c\u01b0\u1eddng \u0111\u1ed9 th\u1ea5p c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u1ea7n t\u1eed nhi\u1ec7t x\u1eed l\u00fd<\/td>\n<\/tr>\n<tr>\n<td>R\u1ee7i ro tr\u00ean m\u1ea1ch \u0111\u1ed9ng c\u01a1<\/td>\n<td>Nguy c\u01a1 ng\u1eaft nh\u1ea7m cao m\u1ed7i l\u1ea7n kh\u1edfi \u0111\u1ed9ng<\/td>\n<td>Ph\u00f9 h\u1ee3p trong h\u1ea7u h\u1ebft c\u00e1c tr\u01b0\u1eddng h\u1ee3p<\/td>\n<\/tr>\n<tr>\n<td>R\u1ee7i ro tr\u00ean m\u1ea1ch chi\u1ebfu s\u00e1ng ho\u1eb7c \u0111i\u1ec7n t\u1eed<\/td>\n<td>Kh\u00f4ng c\u00f3; ph\u00f9 h\u1ee3p<\/td>\n<td>C\u00f3 th\u1ec3 b\u1ecf s\u00f3t ph\u00e1t hi\u1ec7n l\u1ed7i \u0111ang ph\u00e1t tri\u1ec3n<\/td>\n<\/tr>\n<tr>\n<td>\u0110\u1eb7c \u0111i\u1ec3m k\u1ef9 thu\u1eadt \u0111i\u1ec3n h\u00ecnh<\/td>\n<td>Chi\u1ebfu s\u00e1ng d\u00e2n d\u1ee5ng, \u1ed5 c\u1eafm, b\u1ea3ng \u0111i\u1ec1u khi\u1ec3n, thi\u1ebft b\u1ecb \u0111o l\u01b0\u1eddng<\/td>\n<td>\u0110\u1ed9ng c\u01a1, b\u01a1m, HVAC, ph\u00e2n ph\u1ed1i th\u01b0\u01a1ng m\u1ea1i v\u00e0 c\u00f4ng nghi\u1ec7p chung<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>C\u1ea7n l\u01b0u \u00fd r\u1eb1ng c\u00f3 s\u1ef1 ch\u1ed3ng l\u1ea5n gi\u1eefa hai d\u1ea3i: V\u00ed d\u1ee5, m\u1ed9t thi\u1ebft b\u1ecb n\u1eb1m \u1edf \u0111i\u1ec3m gi\u1eefa d\u1ea3i Lo\u1ea1i B (4 \u00d7 In) kh\u00f4ng kh\u00e1c xa so v\u1edbi thi\u1ebft b\u1ecb \u1edf gi\u1edbi h\u1ea1n d\u01b0\u1edbi d\u1ea3i Lo\u1ea1i C (5 \u00d7 In), v\u00e0 th\u1ef1c t\u1ebf c\u00e1c d\u1ea3i n\u00ean \u0111\u01b0\u1ee3c xem l\u00e0 ph\u1ea1m vi, kh\u00f4ng ph\u1ea3i \u0111i\u1ec3m ch\u00ednh x\u00e1c, do sai s\u1ed1 s\u1ea3n xu\u1ea5t. \u0110\u00e2y l\u00e0 l\u00fd do t\u1ea1i sao ng\u1eaft nh\u1ea7m \u0111\u00f4i khi c\u00f3 th\u1ec3 tr\u00e1nh \u0111\u01b0\u1ee3c ch\u1ec9 b\u1eb1ng c\u00e1ch thay \u0111\u1ed5i nh\u00e0 s\u1ea3n xu\u1ea5t, kh\u00f4ng ph\u1ea3i \u0111\u01b0\u1eddng cong, m\u1eb7c d\u00f9 h\u00e0nh \u0111\u1ed9ng \u0111\u00fang l\u00e0 s\u1eed d\u1ee5ng \u0111\u01b0\u1eddng cong ph\u00f9 h\u1ee3p theo th\u00f4ng tin c\u00f4ng b\u1ed1 c\u1ee7a nh\u00e0 s\u1ea3n xu\u1ea5t.<\/p>\n<p>Khi t\u1ea3i g\u1ea7n v\u1edbi m\u1ed9t ranh gi\u1edbi \u2014 ch\u1eb3ng h\u1ea1n nh\u01b0 m\u1ed9t \u0111\u1ed9ng c\u01a1 kh\u1edfi \u0111\u1ed9ng v\u1edbi d\u00f2ng \u0111i\u1ec7n ngay tr\u00ean m\u00e9p c\u1ee7a d\u1ea3i Lo\u1ea1i C \u2014 th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt ph\u1ea3i \u0111\u01b0\u1ee3c x\u00e1c minh d\u1ef1a tr\u00ean d\u1eef li\u1ec7u d\u00f2ng kh\u1edfi \u0111\u1ed9ng th\u1ef1c t\u1ebf c\u1ee7a thi\u1ebft b\u1ecb b\u1ea5t k\u1ec3 c\u00e1c gi\u00e1 tr\u1ecb \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c ph\u00e9p t\u00ednh. Th\u1ef1c t\u1ebf, vi\u1ec7c ch\u1ecdn m\u1ed9t \u0111\u01b0\u1eddng cong d\u1ef1a tr\u00ean quy t\u1eafc ng\u00f3n tay c\u00e1i v\u00e0 sau \u0111\u00f3 ph\u00e1t hi\u1ec7n ra sau khi v\u1eadn h\u00e0nh r\u1eb1ng n\u00f3 kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng c\u00f3 l\u1ebd l\u00e0 l\u00fd do ph\u1ed5 bi\u1ebfn nh\u1ea5t khi\u1ebfn m\u1ed9t b\u1ea3ng \u0111i\u1ec1u khi\u1ec3n ph\u1ea3i \u0111\u01b0\u1ee3c m\u1edf ra. Nguy\u00ean t\u1eafc t\u01b0\u01a1ng t\u1ef1 v\u1ec1 vi\u1ec7c ph\u00f9 h\u1ee3p thi\u1ebft b\u1ecb v\u1edbi t\u1ea3i c\u0169ng \u00e1p d\u1ee5ng cho c\u1ea5u h\u00ecnh c\u1ef1c, v\u00e0 logic l\u1ef1a ch\u1ecdn cho \u0111i\u1ec1u \u0111\u00f3 \u0111\u01b0\u1ee3c tr\u00ecnh b\u00e0y trong h\u01b0\u1edbng d\u1eabn c\u1ee7a ch\u00fang t\u00f4i v\u1ec1 <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/1-pole-vs-2-pole-circuit-breaker\/\">c\u1ea7u dao m\u1ed9t c\u1ef1c v\u00e0 c\u1ea7u dao hai c\u1ef1c<\/a>.<\/p>\n<h2>C\u00e2u h\u1ecfi v\u1ec1 \u201c\u0110\u01b0\u1eddng cong AC\u201d<\/h2>\n<p>Kh\u00f4ng c\u00f3 \u0111\u1ecbnh ngh\u0129a \u201c\u0111\u01b0\u1eddng cong AC\u201d trong IEC 60898-1, v\u00e0 \u0111i\u1ec1u quan tr\u1ecdng l\u00e0 ph\u1ea3i l\u00e0m r\u00f5 \u0111i\u1ec1u n\u00e0y v\u00ec thu\u1eadt ng\u1eef n\u00e0y \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong th\u1ef1c t\u1ebf. Thu\u1eadt ng\u1eef \u201c\u0111\u01b0\u1eddng cong AC\u201d th\u01b0\u1eddng \u0111\u1ec1 c\u1eadp \u0111\u1ebfn m\u1ed9t trong hai \u0111i\u1ec1u sau \u0111\u00e2y.<\/p>\n<ul>\n<li>\u0110i\u1ec1u \u0111\u1ea7u ti\u00ean l\u00e0 ph\u00e2n lo\u1ea1i m\u1ed9t c\u1ea7u dao \u0111\u01b0\u1ee3c \u0111\u1ecbnh m\u1ee9c cho AC v\u00e0 kh\u00f4ng ph\u1ea3i cho DC. \u0110\u00e2y l\u00e0 m\u1ed9t \u0111i\u1ec3m h\u1ee3p l\u1ec7 nh\u01b0ng li\u00ean quan \u0111\u1ebfn \u0111\u1ecbnh m\u1ee9c c\u1ee7a thi\u1ebft b\u1ecb h\u01a1n l\u00e0 ph\u00e2n lo\u1ea1i ch\u00ednh n\u00f3. C\u1ea7u dao AC v\u00e0 DC c\u00f3 thi\u1ebft k\u1ebf kh\u00e1c nhau, v\u00ec vi\u1ec7c d\u1eadp t\u1eaft h\u1ed3 quang trong m\u1ea1ch DC kh\u00f3 h\u01a1n nhi\u1ec1u. \u0110i\u1ec1u n\u00e0y l\u00e0 do d\u00f2ng \u0111i\u1ec7n kh\u00f4ng \u0111\u1ea1t \u0111\u1ebfn zero hai l\u1ea7n trong m\u1ed9t chu k\u1ef3, n\u00ean kh\u00f4ng c\u00f3 \u0111i\u1ec3m t\u1ef1 nhi\u00ean n\u00e0o m\u00e0 h\u1ed3 quang b\u1ecb d\u1eadp t\u1eaft. Do \u0111\u00f3, c\u1ea7u dao \u0111\u1ecbnh m\u1ee9c DC c\u00f3 thi\u1ebft k\u1ebf kh\u00e1c v\u1ec1 m\u00e1ng h\u1ed3 quang, ti\u1ebfp \u0111i\u1ec3m v\u00e0 h\u1ec7 th\u1ed1ng t\u1eeb t\u00ednh, bao g\u1ed3m c\u00e1c \u0111\u01b0\u1eddng cong kh\u00e1c \u0111\u01b0\u1ee3c c\u00f4ng b\u1ed1. Vi\u1ec7c s\u1eed d\u1ee5ng c\u1ea7u dao \u0111\u1ecbnh m\u1ee9c AC trong m\u1ea1ch DC l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a l\u1ed7i \u1ee9ng d\u1ee5ng ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u1ed7i \u0111\u01b0\u1eddng cong.<\/li>\n<li>\u00dd ngh\u0129a th\u1ee9 hai c\u1ee7a thu\u1eadt ng\u1eef n\u00e0y l\u00e0 s\u1ef1 hi\u1ec3u nh\u1ea7m v\u1ec1 Lo\u1ea1i C trong giao ti\u1ebfp. S\u1ef1 nh\u1ea7m l\u1eabn n\u00e0y d\u1ec5 x\u1ea3y ra trong m\u1ed9t x\u01b0\u1edfng l\u00e0m vi\u1ec7c b\u1eadn r\u1ed9n v\u00e0 c\u0169ng qua bi\u00ean gi\u1edbi ng\u00f4n ng\u1eef. Trong c\u00e1c tr\u01b0\u1eddng h\u1ee3p c\u00f3 \u1ee9ng d\u1ee5ng DC th\u1ef1c t\u1ebf \u2014 m\u1ea3ng n\u0103ng l\u01b0\u1ee3ng m\u1eb7t tr\u1eddi, pin, k\u00e9o DC, ngu\u1ed3n \u0111i\u1ec7n vi\u1ec5n th\u00f4ng \u2014 \u0111\u1ecbnh m\u1ee9c v\u00e0 \u0111\u01b0\u1eddng cong DC ph\u00f9 h\u1ee3p n\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng, v\u00e0 c\u1ef1c t\u00ednh c\u0169ng c\u00f3 th\u1ec3 quan tr\u1ecdng. T\u1ed5ng th\u1ec3, n\u1ebfu m\u1ed9t th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt \u0111\u1ec1 c\u1eadp \u0111\u1ebfn \u201c\u0111\u01b0\u1eddng cong AC,\u201d ng\u01b0\u1eddi ta ch\u1ec9 n\u00ean t\u00ecm hi\u1ec3u xem n\u00f3 th\u1ef1c s\u1ef1 c\u00f3 ngh\u0129a l\u00e0 g\u00ec v\u00e0 x\u00e1c nh\u1eadn \u0111\u1ecbnh m\u1ee9c c\u1ee7a thi\u1ebft b\u1ecb tr\u01b0\u1edbc khi \u0111\u1eb7t h\u00e0ng.<\/li>\n<\/ul>\n<h2>C\u00e1ch ch\u1ecdn \u0111\u01b0\u1eddng cong<\/h2>\n<p>Qu\u00e1 tr\u00ecnh ch\u1ecdn \u0111\u01b0\u1eddng cong ph\u00f9 h\u1ee3p l\u00e0 m\u1ed9t th\u1ee7 t\u1ee5c \u0111\u01a1n gi\u1ea3n. N\u00f3 n\u00ean \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n tu\u1ea7n t\u1ef1 v\u00ec b\u1ecf qua vi\u1ec7c ch\u1ecdn \u0111\u01b0\u1eddng cong tr\u01b0\u1edbc khi \u01b0\u1edbc t\u00ednh k\u00edch th\u01b0\u1edbc c\u00e1p c\u00f3 th\u1ec3 l\u00e0 ngu\u1ed3n g\u1ed1c c\u1ee7a c\u00e1c v\u1ea5n \u0111\u1ec1.<\/p>\n<ul>\n<li>T\u00ednh d\u00f2ng t\u1ea3i li\u00ean t\u1ee5c. \u0110i\u1ec1u n\u00e0y x\u00e1c \u0111\u1ecbnh gi\u00e1 tr\u1ecb d\u00f2ng \u0111\u1ecbnh m\u1ee9c (In) c\u1ee7a c\u1ea7u dao, nh\u01b0ng n\u00f3 kh\u00f4ng li\u00ean quan \u0111\u1ebfn \u0111\u01b0\u1eddng cong c\u1ee7a thi\u1ebft b\u1ecb. C\u1ea7u dao \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 b\u1ea3o v\u1ec7 c\u00e1p, c\u00f3 ngh\u0129a l\u00e0 kh\u1ea3 n\u0103ng ch\u1ecbu d\u00f2ng c\u1ee7a c\u00e1p l\u00e0 y\u1ebfu t\u1ed1 gi\u1edbi h\u1ea1n trong qu\u00e1 tr\u00ecnh n\u00e0y.<\/li>\n<li>T\u00ecm gi\u00e1 tr\u1ecb d\u00f2ng kh\u1edfi \u0111\u1ed9ng c\u1ee7a t\u1ea5t c\u1ea3 c\u00e1c th\u00e0nh ph\u1ea7n trong m\u1ea1ch. Trong tr\u01b0\u1eddng h\u1ee3p \u0111\u1ed9ng c\u01a1, n\u00f3 s\u1ebd b\u1eb1ng n\u0103m \u0111\u1ebfn t\u00e1m l\u1ea7n d\u00f2ng ch\u1ea1y, trong khi c\u00e1c lo\u1ea1i t\u1ea3i c\u1ea3m \u1ee9ng nh\u01b0 m\u00e1y bi\u1ebfn \u00e1p c\u00f3 th\u1ec3 t\u1ea1o ra d\u00f2ng \u0111i\u1ec7n g\u1ea5p 10 \u0111\u1ebfn 14 l\u1ea7n ho\u1eb7c h\u01a1n d\u00f2ng \u0111\u1ecbnh m\u1ee9c. \u0110\u00f3ng g\u00f3p t\u1eeb t\u1ea3i \u0111i\u1ec7n tr\u1edf v\u00e0 t\u1ea3i \u0111i\u1ec7n t\u1eed c\u00f3 th\u1ec3 b\u1ecf qua, v\u00ec n\u00f3 g\u1ea7n nh\u01b0 b\u1eb1ng kh\u00f4ng.<\/li>\n<li>T\u00ednh t\u1ef7 l\u1ec7 d\u00f2ng kh\u1edfi \u0111\u1ed9ng tr\u00ean d\u00f2ng \u0111\u1ecbnh m\u1ee9c. N\u1ebfu t\u1ef7 l\u1ec7 n\u00e0y d\u01b0\u1edbi ba l\u1ea7n d\u00f2ng \u0111\u1ecbnh m\u1ee9c, lo\u1ea1i \u0111\u01b0\u1eddng cong B ph\u00f9 h\u1ee3p \u0111\u1ec3 x\u1eed l\u00fd v\u1ea5n \u0111\u1ec1 n\u00e0y. N\u1ebfu t\u1ef7 l\u1ec7 n\u1eb1m trong kho\u1ea3ng t\u1eeb ba \u0111\u1ebfn n\u0103m, lo\u1ea1i B c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng nh\u01b0ng lo\u1ea1i C s\u1ebd l\u00e0 l\u1ef1a ch\u1ecdn \u0111\u00e1ng tin c\u1eady h\u01a1n. N\u1ebfu t\u1ef7 l\u1ec7 cao h\u01a1n n\u0103m, lo\u1ea1i C l\u00e0 l\u1ef1a ch\u1ecdn t\u1ed1t nh\u1ea5t. N\u1ebfu ph\u00e9p t\u00ednh cho th\u1ea5y t\u1ef7 l\u1ec7 cao h\u01a1n m\u01b0\u1eddi l\u1ea7n, \u0111\u01b0\u1eddng cong lo\u1ea1i D n\u00ean \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng.<\/li>\n<li>\u0110\u1ea3m b\u1ea3o xem x\u00e9t lo\u1ea1i c\u00e1p v\u00e0 th\u1eddi gian ng\u1eaft m\u1ea1ch. C\u00e1c lo\u1ea1i \u0111\u01b0\u1eddng cong cao h\u01a1n ho\u1ea1t \u0111\u1ed9ng t\u1ed1t h\u01a1n v\u1edbi d\u00f2ng \u0111i\u1ec7n l\u1edbn, nh\u01b0ng \u0111\u1ed3ng th\u1eddi ch\u00fang kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng \u0111\u00fang trong tr\u01b0\u1eddng h\u1ee3p d\u00f2ng l\u1ed7i trung b\u00ecnh. X\u00e1c minh r\u1eb1ng vi\u1ec7c ng\u1eaft m\u1ea1ch di\u1ec5n ra \u0111\u00fang th\u1eddi \u0111i\u1ec3m ngay c\u1ea3 trong tr\u01b0\u1eddng h\u1ee3p gi\u00e1 tr\u1ecb d\u00f2ng l\u1ed7i th\u1ea5p, \u0111\u1eb7c bi\u1ec7t trong tr\u01b0\u1eddng h\u1ee3p ch\u1ea1y c\u00e1p d\u00e0i.<\/li>\n<li>\u0110\u1ea3m b\u1ea3o r\u1eb1ng t\u1ea5t c\u1ea3 c\u00e1c thi\u1ebft b\u1ecb ph\u00eda tr\u00ean thi\u1ebft b\u1ecb n\u00e0y trong m\u1ea1ch \u0111\u1ec1u \u0111\u01b0\u1ee3c ng\u1eaft k\u1ebft n\u1ed1i khi s\u1eed d\u1ee5ng b\u1ed9 ng\u1eaft m\u1ea1ch c\u1ee5 th\u1ec3 n\u00e0y. Trong tr\u01b0\u1eddng h\u1ee3p thi\u1ebft b\u1ecb lo\u1ea1i D \u0111\u01b0\u1ee3c l\u1eafp \u0111\u1eb7t d\u01b0\u1edbi thi\u1ebft b\u1ecb lo\u1ea1i C trong m\u1ea1ch, ch\u00fang c\u00f3 th\u1ec3 kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng \u0111\u00fang do hi\u1ec7u su\u1ea5t kh\u00e1c nhau c\u1ee7a hai lo\u1ea1i d\u01b0\u1edbi d\u00f2ng l\u1ed7i x\u00e1c \u0111\u1ecbnh.<\/li>\n<li>Ki\u1ec3m tra xem \u0111\u1ecbnh m\u1ee9c c\u1eaft c\u00f3 cao h\u01a1n d\u00f2ng ng\u1eafn m\u1ea1ch d\u1ef1 ki\u1ebfn t\u1ea1i v\u1ecb tr\u00ed l\u1eafp \u0111\u1eb7t hay kh\u00f4ng. Khuy\u1ebfn ngh\u1ecb kh\u00f4ng n\u00ean gi\u1ea3 \u0111\u1ecbnh gi\u00e1 tr\u1ecb c\u1ee7a d\u00f2ng n\u00e0y m\u00e0 n\u00ean t\u00ednh to\u00e1n thay th\u1ebf.<\/li>\n<li>Make sure that the device has passed testing and is certified for use. The following topics are covered in our article regarding UL 489 certification.<\/li>\n<\/ul>\n<p>Once the correct curve is known, the remaining selection is straightforward. A manufacturer offering B, C and D curves across a single certified product family simplifies both specification and spares holding; the <a href=\"https:\/\/huyuglobal.com\/vi\/product\/hum18-63n-mcb-1p-to-4p-63a-type-b-c-d\/\">HUM18-63N range<\/a>, available from 1P to 4P at up to 63 A in B, C and D curves, is an example of that structure and illustrates the specification detail a buyer should expect.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4277\" src=\"https:\/\/huyuglobal.com\/wp-content\/uploads\/2026\/09\/How-to-Select-a-Curve.webp\" alt=\"C\u00e1ch ch\u1ecdn \u0111\u01b0\u1eddng cong\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2>Ambient Temperature and Derating<\/h2>\n<p>When it comes to devices that follow IEC 60898-1, the curve identifies behaviour at a reference temperature, generally at 30\u00b0C. This is due to the fact that the overload element operates on thermal basis, and as a result, its performance changes along the changes in temperature around it, and this is a common reason of unexpected tripping in installations.<\/p>\n<p>In the case of a hot environment, e.g. for a panel during a hot day, a distribution board in a box exposed to sun, or a breaker next to equipment that produces heat, the bimetallic strip has a higher starting point and reaches its trip point at lower current, which is significant, as manufacturers have tables showing how devices with 20A operating at 60\u00b0c would carry a much lesser current, and vice versa, when the unit is functioned at lower temperature level, it would trip at a higher current level.<\/p>\n<p>There are three things worth mentioning. First, when placing devices in warm spots one may select breaker rating based on derating tables data rather than nominal value, which may indicate the need to pick a higher rating. Second, devices installed close together in panels impact each other by means that the manufacturer\u2019s factor has to be added to the ambient correction. Third, if circuit trips only on hot afternoons, it is rather a case of derating issue as opposed to the fault in operation. Where a device is genuinely suspect, the diagnostic approach in our guide to <a href=\"https:\/\/huyuglobal.com\/vi\/blog\/how-to-tell-if-a-breaker-is-bad\/\">identifying a failed breaker<\/a> is the place to start.<\/p>\n<h2>Common Mistakes<\/h2>\n<ul>\n<li>Increasing ampacity rather than modifying the curve is the most severe mistake in this field. Installing a 32 A circuit breaker within a circuit wired using a 20 A electric cable implies that the wires may get hot and insulation may deteriorate before the circuit breaker even operates. In essence, the circuit breaker offers protection to the wire more than to the load.<\/li>\n<li>Installing type D circuit breakers in less specific situations. Type D has the capacity to withstand inrushes but allows moderate fault currents for longer periods which may go unnoticed in susceptible circuits. Type D circuit breakers should only be used for high inrushing situations.<\/li>\n<li>Ignoring ambient correction factor. Sometimes a seemingly correct device may turn out to be wrong due to high temperatures.<\/li>\n<li>Mistaking B, C and D across different manufacturers. There are standards for the bands, but that does not mean that tolerances and the shape of curves remain the same; so it is wise to check the curves manufactured by a specific manufacturer rather than use the approximate values.<\/li>\n<li>Using an AC-rated device on DC current. Direct current requires much more complicated processes.<\/li>\n<li>Neglecting coordination. Even if devices are correctly selected they still may trip incorrectly because of coordination error.<\/li>\n<li>Selecting a curve prior to selecting a cable. The cable defines the rating of the circuit breaker, and the load determines the curve; otherwise, the installation may appear to have followed the rules while not being safe at all.<\/li>\n<\/ul>\n<h2>Standards and Certification<\/h2>\n<p>Which standard applies determines which curves exist, what the device is tested to, and what the markings mean.<\/p>\n<table>\n<tbody>\n<tr>\n<th>Ti\u00eau chu\u1ea9n<\/th>\n<th>Applies to<\/th>\n<th>Curve characteristics<\/th>\n<\/tr>\n<tr>\n<td>IEC\/EN 60898-1<\/td>\n<td>Miniature circuit breakers for household and similar installations<\/td>\n<td>Fixed B, C and D curves with defined magnetic bands; domestic and light commercial<\/td>\n<\/tr>\n<tr>\n<td>IEC\/EN 60947-2<\/td>\n<td>Circuit breakers for industrial installations, including MCCBs<\/td>\n<td>Often adjustable thermal and magnetic settings; used where coordination across a system is required<\/td>\n<\/tr>\n<tr>\n<td>UL 489<\/td>\n<td>Moulded-case circuit breakers for the North American market<\/td>\n<td>Uses different trip-band conventions; devices are not interchangeable with IEC curve types<\/td>\n<\/tr>\n<tr>\n<td>UL 1077<\/td>\n<td>Supplementary protectors<\/td>\n<td>Not branch-circuit protective devices; must not be substituted for a UL 489 breaker<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The North American distinction causes buyers who operate in multiple markets difficulty. A device that is labeled as &#8220;Type C&#8221; per IEC 60898-1 and a device that has a C-something catalog number per UL 489 are not the same thing and operate with different trip characteristics. This is particularly important when a single project crosses standards, such as a European panel that must be installed on a North American site: the certification is determined by the law at the installation site, which means that the device must be certified accordingly. The same rationale applies to the auxiliary functions provided by some of these devices: the certification must match the panel, not the catalog name.<\/p>\n<h2>C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/h2>\n<h3>What does it mean to be a curve breaker?<\/h3>\n<p>This implies that the behavior of the circuit breaker in terms of tripping is based on a published time-current curve instead of one fixed trip value. Such a curve gives information on the operating time of the device for each multiple of rated current, giving the bottom line about the two types of tripping: a slow thermal one which protects conductors against overloading and instantaneous magnetic one which protects against short circuits. The letter indicating the type of circuitry on the device &#8211; B, C or D according to IEC 60898-1 &#8211; indicates the multiple to which the particular device belongs: 3-5, 5-10 and 10-20 times of rated current, respectively. The working principle of the curve is to determine the trip time rather the maximum current the device can carry.<\/p>\n<h3>What are the three types of breakers?<\/h3>\n<p>The standard types in the IEC 60898-1 family are three. The first type is type B with its magnetic trip range of 3 to 5 times the rated current; type C with a magnetic trip of 5 to 10 times rated current; and type D of 10 to 20 times rated current. The type B is suitable for loads that have minimal or negligible inrush, such as lighting, resistance heating, socket outlets and control instruments. Type C is the preferred type for mixed loads and for normal motors which makes it the most frequently used specification in commercial and industrial distribution. Type D is used for equipment that has big inrush loads, like large transformers, welders, generators, X-ray machines and big motors. Apart from these three types, there exist the types A, Z and K designed for specific applications and modern molded circuit breakers usually come with adjustable settings as opposed to fixed ones.<\/p>\n<h3>What does the AC curve breaker mean?<\/h3>\n<p>The term &#8220;AC curve&#8221; does not specifically exist in the IEC 60898-1 standard. In reality, &#8220;AC curve&#8221; could refer to either of two meanings. For example, it can relate to a device rated for AC service instead of DC service since breaking of arcs is considerably more difficult for DC due to the constant flow of electrical current. Devices rated specifically for DC operations have specially developed devices such as arc chutes and contacts. An &#8220;AC curve&#8221; could also mean type C as a result of malapropism or misunderstanding. It is important to be cautious when using this term since any order needs to indicate the intended meaning of &#8220;AC curve&#8221;. For application which actually requires working in DC mode such as photovoltaic solar cells or battery storage it is critically important to rely strictly on the devices that are rated for DC operations and use DC curves only by the manufacturers.<\/p>\n<h3>What&#8217;s the difference between B curve and C curve breakers?<\/h3>\n<p>The distinction comes down to the magnetic tripping curve. A Type B breaker trips at 3-5 times its rated current, whereas Type C trips at 5-10 times. In all other regards \u2014 that is, thermal overload mechanism, continuous current capacity, and size \u2014 they are practically identical. In practice, Type B is more sensitive, which is why it is good at identifying emerging fault conditions in low-inrush circuits; however, it also trips in case of motor startup. Type C is capable of withstanding the five to eight times inrush current produced by the motor while still being sufficiently sensitive for general use. Therefore, it tends to be the default circuit breaker in industrial and commercial installations. In theory, it is not that one type of circuit breaker is better than the other; any of them is appropriate for operating in its own conditions.<\/p>\n<h3>Can I fix nuisance tripping by fitting a bigger breaker?<\/h3>\n<p>No, this task is very dangerous to do. The amperage rating of a breaker is based on the current-carrying capacity of the wires it protects (typically a 15 A circuit is connected to 14 AWG wires, while a 20 A circuit is normally wired with 12 AWG cables). This means that connecting a 32 A breaker to a 20 A wire may result in an overheating wire which has no protection against overheating and may catch fire. Whenever there is a nuisance tripping problem on the motor circuit, one should rather consider it a curve problem than a rating issue and fix the issue by going from Type B to Type C or from C to D (if the inrush can justify this), while verifying the result on the actual inrush value rather than on speculation.<\/p>\n<h2>T\u00e0i li\u1ec7u tham kh\u1ea3o<\/h2>\n<ul>\n<li><a href=\"https:\/\/www.iec.ch\/\" rel=\"nofollow noopener\" target=\"_blank\">International Electrotechnical Commission \u2014 IEC 60898-1 Circuit Breakers for Household and Similar Installations<\/a><\/li>\n<li><a href=\"https:\/\/www.iec.ch\/\" rel=\"nofollow noopener\" target=\"_blank\">International Electrotechnical Commission \u2014 IEC 60947-2 Circuit Breakers for Industrial Installations<\/a><\/li>\n<li><a href=\"https:\/\/www.ul.com\/\" rel=\"nofollow noopener\" target=\"_blank\">UL Solutions \u2014 UL 489 Molded-Case Circuit Breakers and UL 1077 Supplementary Protectors<\/a><\/li>\n<li><a href=\"https:\/\/www.bsigroup.com\/\" rel=\"nofollow noopener\" target=\"_blank\">BSI \u2014 BS EN 60898-1 Requirements for MCB Trip Characteristics<\/a><\/li>\n<li><a href=\"https:\/\/www.nfpa.org\/\" rel=\"nofollow noopener\" target=\"_blank\">NFPA \u2014 National Electrical Code, Article 240 Overcurrent Protection<\/a><\/li>\n<\/ul>\n<h2>K\u1ebft lu\u1eadn<\/h2>\n<p>A curve breaker is merely a certain kind of breaker with its particular behaviour being identified by a curve, the only thing that varies with different curves being the current value at which magnetic device will operate. Type B operates at three to five times the nominal current and is appropriate for the loads whose launch is close to smooth; Type C at five to 10 times and is appropriate for the motor and mixed loads dominating typical installations; Type D at 10-20 and exists for transformers, welding machines, and huge equipment emitting such a pulse that the correctly selected breaker would trip all the time. The thermal overload response of all the devices is the same; that\u2019s the point that removes any confusion since it is evident that the curve is about the inrush discrimination and not about the protection capability. In order to avoid nuisance tripping, just define the cable rating, the curve based on the load\u2019s inrush curve, check that the above selected device reacts in short time in case of the lowest fault current, use derating factors and check the coordination with upstream devices.<\/p>","protected":false},"excerpt":{"rendered":"<p>A curve breaker may not be a new kind of breaker but refers to a breaker whose trip time is determined by a curve that has been preset so that it allows the circuit to trip every time a motor is switched on or stay closed when a wire is burning. It is easy to [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":4278,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_gspb_post_css":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-4275","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blogs"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts\/4275","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/comments?post=4275"}],"version-history":[{"count":2,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts\/4275\/revisions"}],"predecessor-version":[{"id":4280,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/posts\/4275\/revisions\/4280"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/media\/4278"}],"wp:attachment":[{"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/media?parent=4275"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/categories?post=4275"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/huyuglobal.com\/vi\/wp-json\/wp\/v2\/tags?post=4275"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}