{"id":15866,"date":"2026-01-07T11:45:39","date_gmt":"2026-01-07T03:45:39","guid":{"rendered":"http:\/\/www.erun-tech.com\/?post_type=dt_portfolio&p=15866"},"modified":"2026-01-07T11:45:39","modified_gmt":"2026-01-07T03:45:39","slug":"diandongjizhuhuiluduanluyuquexiangguzhangfenxiyupaichu","status":"publish","type":"dt_portfolio","link":"http:\/\/www.erun-tech.com\/vi\/project\/diandongjizhuhuiluduanluyuquexiangguzhangfenxiyupaichu","title":{"rendered":"Ph\u00e2n t\u00edch v\u00e0 kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1 ch\u1eadp m\u1ea1ch v\u00e0 m\u1ea5t pha trong m\u1ea1ch ch\u00ednh c\u1ee7a \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n"},"content":{"rendered":"
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Ph\u00e2n t\u00edch v\u00e0 kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1 ch\u1eadp m\u1ea1ch v\u00e0 m\u1ea5t pha trong m\u1ea1ch ch\u00ednh c\u1ee7a \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n<\/h1>\n
An to\u00e0n m\u1ea1ch \u0111\u1ea3o chi\u1ec1u \u00b7 Ch\u1ea9n \u0111o\u00e1n s\u1ef1 c\u1ed1 \u00b7 B\u1ea3o tr\u00ec h\u1ec7 th\u1ed1ng \u0111i\u1ec7n tr\u00ean t\u00e0u<\/div>\n<\/div>\n
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\u1ee8ng d\u1ee5ng c\u1ee7a m\u1ea1ch \u0111\u1ea3o chi\u1ec1u tr\u00ean t\u00e0u bi\u1ec3n l\u00e0 v\u00f4 c\u00f9ng quan tr\u1ecdng; c\u00e1c thi\u1ebft b\u1ecb n\u00e0y bao g\u1ed3m nh\u01b0ng kh\u00f4ng gi\u1edbi h\u1ea1n \u1edf m\u00e1y cu\u1ed9n d\u00e2y, m\u00e1y n\u00e2ng h\u00e0ng, m\u00e1y th\u1ea3 neo, thang l\u00ean xu\u1ed1ng t\u00e0u v\u00e0 c\u00e1c lo\u1ea1i m\u00e1y m\u00f3c ph\u1ee5 tr\u1ee3 kh\u00e1c (nh\u01b0 m\u00e1y b\u01a1m v\u00e0 qu\u1ea1t gi\u00f3). Trong qu\u00e1 tr\u00ecnh thi\u1ebft k\u1ebf, \u0111\u1ec3 ng\u0103n ng\u1eeba c\u00e1c s\u1ef1 c\u1ed1 an to\u00e0n do ch\u1eadp \u0111i\u1ec7n ho\u1eb7c c\u00e1c s\u1ef1 c\u1ed1 \u0111i\u1ec7n kh\u00e1c g\u00e2y ra, t\u1ea5t c\u1ea3 c\u00e1c m\u1ea1ch \u0111\u1ea3o chi\u1ec1u \u0111\u1ec1u ph\u1ea3i \u0111\u01b0\u1ee3c trang b\u1ecb c\u01a1 ch\u1ebf kh\u00f3a li\u00ean \u0111\u1ed9ng, bao g\u1ed3m nh\u01b0ng kh\u00f4ng gi\u1edbi h\u1ea1n \u1edf kh\u00f3a li\u00ean \u0111\u1ed9ng c\u01a1 kh\u00ed v\u00e0 kh\u00f3a li\u00ean \u0111\u1ed9ng \u0111i\u1ec7n, nh\u1eb1m \u0111\u1ea3m b\u1ea3o c\u00e1c c\u00f4ng t\u1eafc t\u01a1 hai chi\u1ec1u kh\u00f4ng \u0111\u00f3ng c\u00f9ng l\u00fac.<\/p>\n<\/section>\n

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I. Ph\u00e2n t\u00edch v\u00e0 kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1 ch\u1eadp m\u1ea1ch trong m\u1ea1ch ch\u00ednh c\u1ee7a \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n<\/h2>\n
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Ng\u1eafn m\u1ea1ch l\u00e0 m\u1ed9t tr\u1ea1ng th\u00e1i s\u1ef1 c\u1ed1 trong m\u1ea1ch \u0111i\u1ec7n, trong \u0111\u00f3 d\u00f2ng \u0111i\u1ec7n kh\u00f4ng \u0111i qua t\u1ea3i d\u1ef1 ki\u1ebfn (nh\u01b0 \u0111i\u1ec7n tr\u1edf, b\u00f3ng \u0111\u00e8n ho\u1eb7c c\u00e1c thi\u1ebft b\u1ecb ti\u00eau th\u1ee5 \u0111i\u1ec7n kh\u00e1c), m\u00e0 \u0111i qua m\u1ed9t \u0111\u01b0\u1eddng d\u1eabn c\u00f3 \u0111i\u1ec7n tr\u1edf th\u1ea5p v\u00e0 quay tr\u1edf l\u1ea1i tr\u1ef1c ti\u1ebfp ngu\u1ed3n \u0111i\u1ec7n. Trong \u0111i\u1ec1u ki\u1ec7n l\u00fd t\u01b0\u1edfng, d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch \u0111i\u1ec7n ph\u1ea3i \u0111i qua t\u1ea5t c\u1ea3 c\u00e1c th\u00e0nh ph\u1ea7n \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf, bao g\u1ed3m c\u00e1c thi\u1ebft b\u1ecb \u0111i\u1ec7n v\u00e0 thi\u1ebft b\u1ecb b\u1ea3o v\u1ec7. Tuy nhi\u00ean, trong tr\u01b0\u1eddng h\u1ee3p ng\u1eafn m\u1ea1ch, d\u00f2ng \u0111i\u1ec7n s\u1ebd b\u1ecf qua c\u00e1c th\u00e0nh ph\u1ea7n n\u00e0y v\u00e0 t\u00ecm m\u1ed9t \u0111\u01b0\u1eddng d\u1eabn c\u00f3 \u0111i\u1ec7n tr\u1edf nh\u1ecf h\u01a1n; \u0111i\u1ec1u n\u00e0y th\u01b0\u1eddng c\u00f3 ngh\u0129a l\u00e0 d\u00f2ng \u0111i\u1ec7n s\u1ebd ch\u1ea3y tr\u1ef1c ti\u1ebfp t\u1eeb c\u1ef1c n\u00e0y sang c\u1ef1c kia c\u1ee7a ngu\u1ed3n \u0111i\u1ec7n m\u00e0 kh\u00f4ng \u0111i qua b\u1ea5t k\u1ef3 t\u1ea3i n\u00e0o ho\u1eb7c ch\u1ec9 \u0111i qua r\u1ea5t \u00edt t\u1ea3i.<\/p>\n

1. C\u00e1c lo\u1ea1i ng\u1eafn m\u1ea1ch<\/h3>\n
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(1) Ch\u1eadp m\u1ea1ch gi\u1eefa c\u00e1c pha<\/strong>
\nTrong h\u1ec7 th\u1ed1ng \u0111i\u1ec7n ba pha, c\u00f3 th\u1ec3 x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng k\u1ebft n\u1ed1i b\u1ea5t th\u01b0\u1eddng gi\u1eefa c\u00e1c pha. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y c\u00f3 th\u1ec3 xu\u1ea5t hi\u1ec7n tr\u00ean thi\u1ebft b\u1ecb ti\u00eau th\u1ee5 \u0111i\u1ec7n ho\u1eb7c tr\u00ean \u0111\u01b0\u1eddng d\u00e2y.<\/span><\/div>\n
(2) Ch\u1eadp m\u1ea1ch v\u1edbi \u0111\u1ea5t<\/strong>
\nS\u1ef1 ti\u1ebfp x\u00fac b\u1ea5t th\u01b0\u1eddng gi\u1eefa m\u1ed9t ho\u1eb7c nhi\u1ec1u d\u00e2y d\u1eabn mang \u0111i\u1ec7n v\u1edbi m\u1eb7t \u0111\u1ea5t (ho\u1eb7c b\u1ed9 ph\u1eadn kim lo\u1ea1i \u0111\u01b0\u1ee3c n\u1ed1i \u0111\u1ea5t).<\/span><\/div>\n<\/div>\n

2. Nguy\u00ean nh\u00e2n g\u00e2y ra s\u1ef1 c\u1ed1 ch\u1eadp m\u1ea1ch trong m\u1ea1ch ch\u00ednh<\/h3>\n

H\u00ecnh 21-1 minh h\u1ecda m\u1ea1ch \u0111i\u1ec1u khi\u1ec3n quay thu\u1eadn v\u00e0 quay ng\u01b0\u1ee3c c\u1ee7a \u0111\u1ed9ng c\u01a1. \u0110\u1ec3 ng\u0103n ng\u1eeba va \u0111\u1eadp c\u01a1 h\u1ecdc ho\u1eb7c qu\u00e1 t\u1ea3i \u0111i\u1ec7n do \u0111\u1ed9ng c\u01a1 ch\u01b0a d\u1eebng h\u1eb3n v\u00ec qu\u00e1n t\u00ednh khi chuy\u1ec3n \u0111\u1ed5i h\u01b0\u1edbng quay, m\u1ed9t s\u1ed1 m\u1ea1ch \u0111i\u1ec1u khi\u1ec3n quay thu\u1eadn v\u00e0 quay ng\u01b0\u1ee3c s\u1ebd \u0111\u01b0\u1ee3c trang b\u1ecb r\u01a1le th\u1eddi gian. Trong h\u00ecnh v\u1ebd, c\u00f3 th\u1ec3 gi\u1ea3 \u0111\u1ecbnh r\u1eb1ng c\u00f4ng t\u1eafc \u0111i\u1ec7n KM\u2081 l\u00e0 c\u00f4ng t\u1eafc \u0111i\u1ec7n cho ch\u1ebf \u0111\u1ed9 quay thu\u1eadn, KM\u2082 l\u00e0 c\u00f4ng t\u1eafc \u0111i\u1ec7n cho ch\u1ebf \u0111\u1ed9 quay ng\u01b0\u1ee3c, SB\u2082 l\u00e0 n\u00fat kh\u1edfi \u0111\u1ed9ng ch\u1ebf \u0111\u1ed9 quay thu\u1eadn, SB\u2083 l\u00e0 n\u00fat kh\u1edfi \u0111\u1ed9ng ch\u1ebf \u0111\u1ed9 quay ng\u01b0\u1ee3c, v\u00e0 SB\u2081 l\u00e0 n\u00fat d\u1eebng chung.<\/p>\n

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\"36c8146010c34b27136f663aa4975ed6\"H\u00ecnh 21-1: M\u1ea1ch \u0111i\u1ec1u khi\u1ec3n quay thu\u1eadn v\u00e0 quay ng\u01b0\u1ee3c c\u1ee7a \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n<\/p>\n<\/div>\n

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(1) Ch\u1eadp m\u1ea1ch gi\u1eefa c\u00e1c pha trong m\u1ea1ch ch\u00ednh:<\/strong>C\u00f3 th\u1ec3 x\u1ea3y ra t\u1ea1i b\u1ea5t k\u1ef3 v\u1ecb tr\u00ed n\u00e0o tr\u00ean m\u1ea1ch ch\u00ednh. Ch\u1ec9 c\u1ea7n hai trong s\u1ed1 c\u00e1c d\u00e2y c\u00e1p U\u2081, V\u2081 v\u00e0 W\u2081 kh\u00f4ng ti\u1ebfp x\u00fac tr\u1ef1c ti\u1ebfp v\u1edbi thi\u1ebft b\u1ecb ti\u00eau th\u1ee5 \u0111i\u1ec7n l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y c\u00f3 th\u1ec3 x\u1ea3y ra. C\u00e1c nguy\u00ean nh\u00e2n c\u1ee5 th\u1ec3 bao g\u1ed3m:<\/p>\n

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  • \u25cf C\u00e1c ti\u1ebfp \u0111i\u1ec3m ch\u00ednh c\u1ee7a r\u01a1le b\u1ecb d\u00ednh:<\/strong>C\u00e1c ti\u1ebfp \u0111i\u1ec3m ch\u00ednh KM\u2081 ho\u1eb7c KM\u2082 b\u1ecb h\u00e0n d\u00ednh ho\u1eb7c k\u1eb9t c\u01a1 h\u1ecdc. N\u1ebfu l\u00fac n\u00e0y nh\u1ea5n n\u00fat kh\u1edfi \u0111\u1ed9ng \u0111\u1ea3o chi\u1ec1u, s\u1ebd d\u1eabn \u0111\u1ebfn hi\u1ec7n t\u01b0\u1ee3ng ch\u1eadp m\u1ea1ch gi\u1eefa hai pha ngu\u1ed3n \u0111i\u1ec7n. C\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0111\u1ed3ng h\u1ed3 v\u1ea1n n\u0103ng \u0111\u1ec3 \u0111o xem hai \u0111\u1ea7u tr\u00ean v\u00e0 d\u01b0\u1edbi c\u1ee7a r\u01a1le c\u00f3 b\u1ecb ng\u1eaft k\u1ebft n\u1ed1i hay kh\u00f4ng nh\u1eb1m x\u00e1c \u0111\u1ecbnh t\u00ecnh tr\u1ea1ng n\u00e0y.<\/li>\n
  • \u25cf L\u1ed7i kh\u00f3a li\u00ean \u0111\u1ed9ng:<\/strong>Ti\u1ebfp \u0111i\u1ec3m th\u01b0\u1eddng \u0111\u00f3ng c\u1ee7a KM\u2082 trong m\u1ea1ch \u0111i\u1ec1u khi\u1ec3n b\u1ecb d\u00ednh. N\u1ebfu nh\u1ea5n n\u00fat \u0111\u1ea3o chi\u1ec1u SB\u2083 khi \u0111\u1ed9ng c\u01a1 \u0111ang quay theo chi\u1ec1u thu\u1eadn, c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn ng\u1eafn m\u1ea1ch trong m\u1ea1ch ch\u00ednh.<\/li>\n
  • \u25cf C\u00e1c y\u1ebfu t\u1ed1 v\u1eadt l\u00fd:<\/strong>C\u00e1c nguy\u00ean nh\u00e2n nh\u01b0 d\u00e2y trong h\u1ed9p n\u1ed1i b\u1ecb l\u1ecfng, l\u1edbp c\u00e1ch \u0111i\u1ec7n b\u1ecb h\u01b0 h\u1ecfng do rung \u0111\u1ed9ng v\u00e0 ma s\u00e1t, m\u00f4i tr\u01b0\u1eddng qu\u00e1 \u1ea9m \u01b0\u1edbt (n\u01b0\u1edbc x\u00e2m nh\u1eadp v\u00e0o h\u1ed9p n\u1ed1i), v.v.<\/li>\n<\/ul>\n

    (2) Ch\u1eadp m\u1ea1ch gi\u1eefa c\u00e1c v\u00f2ng d\u00e2y c\u1ee7a \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n:<\/strong>L\u00e0 hi\u1ec7n t\u01b0\u1ee3ng ch\u1eadp m\u1ea1ch x\u1ea3y ra gi\u1eefa c\u00e1c cu\u1ed9n d\u00e2y (v\u00f2ng d\u00e2y) li\u1ec1n k\u1ec1 trong c\u00f9ng m\u1ed9t cu\u1ed9n d\u00e2y do h\u01b0 h\u1ecfng l\u1edbp c\u00e1ch \u0111i\u1ec7n. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y c\u00f3 th\u1ec3 g\u00e2y ra m\u1ea5t c\u00e2n b\u1eb1ng d\u00f2ng \u0111i\u1ec7n, qu\u00e1 nhi\u1ec7t v\u00e0 h\u01b0 h\u1ecfng c\u01a1 h\u1ecdc. C\u00f3 th\u1ec3 ti\u1ebfn h\u00e0nh \u0111\u00e1nh gi\u00e1 s\u01a1 b\u1ed9 b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng \u0111\u1ed3ng h\u1ed3 v\u1ea1n n\u0103ng \u0111\u1ec3 \u0111o xem \u0111i\u1ec7n tr\u1edf c\u1ee7a ba pha trong cu\u1ed9n d\u00e2y c\u00f3 x\u1ea5p x\u1ec9 b\u1eb1ng nhau hay kh\u00f4ng.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

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    II. Ph\u00e2n t\u00edch v\u00e0 kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1 m\u1ea5t pha trong m\u1ea1ch ch\u00ednh c\u1ee7a \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n<\/h2>\n
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    C\u00e1c \u0111\u1eb7c tr\u01b0ng v\u1eadt l\u00fd c\u1ee7a hi\u1ec7n t\u01b0\u1ee3ng m\u1ea5t pha:<\/strong>\u0110\u1ed9ng c\u01a1 rung m\u1ea1nh h\u01a1n, nhi\u1ec7t \u0111\u1ed9 t\u0103ng cao, t\u1ed1c \u0111\u1ed9 quay gi\u1ea3m, d\u00f2ng \u0111i\u1ec7n t\u0103ng v\u00e0 ph\u00e1t ra ti\u1ebfng \u1ed3n l\u1ea1 nh\u01b0 ti\u1ebfng \u201c\u00f9 \u00f9\u201d. N\u1ebfu c\u00e1c b\u1ed9 ph\u1eadn b\u1ea3o v\u1ec7 kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng, \u0111\u1ed9ng c\u01a1 c\u00f3 th\u1ec3 ti\u1ebfp t\u1ee5c ch\u1ea1y nh\u01b0ng r\u1ea5t d\u1ec5 b\u1ecb ch\u00e1y; sau khi d\u1eebng l\u1ea1i, khi kh\u1edfi \u0111\u1ed9ng l\u1ea1i s\u1ebd ph\u00e1t ra ti\u1ebfng \u1ed3n r\u1ea5t l\u1edbn v\u00e0 kh\u00f4ng th\u1ec3 kh\u1edfi \u0111\u1ed9ng th\u00e0nh c\u00f4ng.<\/div>\n

    Quy tr\u00ecnh kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1<\/h3>\n
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    \u25cf Ph\u00eda ngu\u1ed3n \u0111i\u1ec7n v\u00e0 c\u1ea7u ch\u00ec:<\/strong>
    \n\u0110o \u0111i\u1ec7n \u00e1p gi\u1eefa c\u00e1c \u0111o\u1ea1n L\u2081-L\u2082, L\u2082-L\u2083 v\u00e0 L\u2081-L\u2083. N\u1ebfu c\u1ea7u ch\u00ec (FU\u2081) b\u1ecb ch\u00e1y, c\u00f3 th\u1ec3 x\u00e1c nh\u1eadn b\u1eb1ng ph\u01b0\u01a1ng ph\u00e1p ki\u1ec3m tra khi ng\u1eaft \u0111i\u1ec7n (ki\u1ec3m tra tr\u1ea1ng th\u00e1i \u0111\u00f3ng\/m\u1edf) ho\u1eb7c ph\u01b0\u01a1ng ph\u00e1p ki\u1ec3m tra khi c\u00f3 \u0111i\u1ec7n (\u0111o \u0111i\u1ec7n \u00e1p \u1edf hai \u0111\u1ea7u).<\/span><\/div>\n
    \u25cf Thi\u1ebft b\u1ecb \u0111i\u1ec7n v\u00e0 h\u1ec7 th\u1ed1ng d\u00e2y \u0111i\u1ec7n:<\/strong>
    \nKi\u1ec3m tra xem c\u00e1c \u0111\u1ea7u n\u1ed1i c\u00f3 b\u1ecb l\u1ecfng ho\u1eb7c \u0111\u1ee9t kh\u00f4ng; quan s\u00e1t xem c\u00e1c ti\u1ebfp \u0111i\u1ec3m c\u1ee7a r\u01a1le ti\u1ebfp x\u00fac c\u00f3 b\u1ecb m\u00f2n nghi\u00eam tr\u1ecdng hay kh\u00f4ng. N\u1ebfu r\u01a1le nhi\u1ec7t (FR) ch\u1ec9 ho\u1ea1t \u0111\u1ed9ng \u1edf m\u1ed9t pha thay v\u00ec ho\u1ea1t \u0111\u1ed9ng \u0111\u1ed3ng b\u1ed9 \u1edf c\u1ea3 ba pha, \u0111i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 ch\u00ednh r\u01a1le nhi\u1ec7t \u0111\u00e3 b\u1ecb h\u1ecfng.<\/span><\/div>\n
    \u25cf Cu\u1ed9n d\u00e2y \u0111\u1ed9ng c\u01a1:<\/strong>
    \n\u0110\u1ee9t m\u1ea1ch cu\u1ed9n d\u00e2y b\u00ean trong. Khi \u0111o, c\u1ea7n ng\u1eaft k\u1ebft n\u1ed1i t\u1ea5m n\u1ed1i sao-tam gi\u00e1c, sau \u0111\u00f3 \u0111o \u0111i\u1ec7n tr\u1edf gi\u1eefa c\u00e1c c\u1eb7p U\u2081-U\u2082, V\u2081-V\u2082 v\u00e0 W\u2081-W\u2082.<\/span><\/div>\n<\/div>\n
    \n

    T\u1ed5ng k\u1ebft c\u00f4ng t\u00e1c b\u1ea3o tr\u00ec t\u1ed5ng h\u1ee3p<\/h4>\n

    Cho d\u00f9 l\u00e0 c\u1ea7u ch\u00ec b\u1ecb ch\u00e1y, r\u01a1le ti\u1ebfp \u0111i\u1ec3m b\u1ecb h\u1ecfng hay r\u01a1le nhi\u1ec7t b\u1ecb h\u1ecfng, t\u1ea5t c\u1ea3 \u0111\u1ec1u cho th\u1ea5y m\u1ea1ch \u0111i\u1ec7n c\u00f3 s\u1ef1 c\u1ed1. Khi thay th\u1ebf linh ki\u1ec7n, ngo\u00e0i vi\u1ec7c ch\u00fa \u00fd \u0111\u1ebfn vi\u1ec7c \u0111\u1ea3m b\u1ea3o th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt ph\u00f9 h\u1ee3p,Ph\u1ea3i \u0111\u1ea3m b\u1ea3o \u0111\u1ed9ng c\u01a1 v\u00e0 to\u00e0n b\u1ed9 m\u1ea1ch \u0111i\u1ec7n \u0111ang \u1edf tr\u1ea1ng th\u00e1i ho\u1ea1t \u0111\u1ed9ng t\u1ed1t<\/strong>. Trong giai \u0111o\u1ea1n \u0111\u1ea7u v\u1eadn h\u00e0nh sau khi c\u1ea5p \u0111i\u1ec7n, c\u1ea7n ch\u00fa tr\u1ecdng c\u00e1c v\u1ea5n \u0111\u1ec1 sau:
    \n1. Gi\u00e1 tr\u1ecb d\u00f2ng \u0111i\u1ec7n c\u1ee7a \u0111\u1ed9ng c\u01a1;
    \n2. Ti\u1ebfng \u1ed3n khi v\u1eadn h\u00e0nh (v\u00f2ng bi v\u00e0 t\u1ea3i);
    \n3. Nhi\u1ec7t \u0111\u1ed9 \u0111\u1ed9ng c\u01a1 (ch\u00fa \u00fd \u0111\u1eb7c bi\u1ec7t \u0111\u1ebfn nhi\u1ec7t \u0111\u1ed9 \u1edf hai \u0111\u1ea7u \u1ed5 tr\u1ee5c).<\/p>\n<\/div>\n<\/div>\n<\/section>\n