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MCB intelligent

ĮŶĚ ƚŚĞƌĞ ĂƌĞ ŵĂŝŶůLJ ŽŶĞ ďŝ Ͳ ŵĞƚĂůůŝĐ ƐƚƌŝƉ͕ ŽŶĞ ǁŝůů ŽƉĞŶ ŝŶ ƐĂŵĞ ŵĂŶŶĞƌ͘ ŐĂŝŶ ǁŚĞŶ ŽƉĞƌĂƟŶŐ
ƚƌŝƉ ĐŽŝů ĂŶĚ ŽŶĞ ŚĂŶĚ ŽƉĞƌĂƚĞĚ ŽŶ Ͳ Žī ůĞǀĞƌ͘ lever of the miniature circuit breaker is operated
Electric current carrying path of a miniature circuit by hand, that means when we make the MCB
breaker shown in the picture is like follows. First Ăƚ Žī ƉŽƐŝƟŽŶ ŵĂŶƵĂůůLJ͕ ƚŚĞ ƐĂŵĞ ůĂƚĐŚ ƉŽŝŶƚ ŝƐ
ůĞŌ ŚĂŶĚ ƐŝĚĞ ƉŽǁĞƌ ƚĞƌŵŝŶĂů Ͳ ƚŚĞŶ ďŝŵĞƚĂůůŝĐ displaced as a result moving contact separated
strip - then current coil or trip coil - then moving ĨƌŽŵ ĮdžĞĚ ĐŽŶƚĂĐƚ ŝŶ ƐĂŵĞ ŵĂŶŶĞƌ͘ ^Ž͕ ǁŚĂƚĞǀĞƌ
ĐŽŶƚĂĐƚ Ͳ ƚŚĞŶ ĮdžĞĚ ĐŽŶƚĂĐƚ ĂŶĚ Ͳ ůĂƐƚůLJ ƌŝŐŚƚ ŚĂĚ ŵĂLJ ďĞ ƚŚĞ ŽƉĞƌĂƟŶŐ ŵĞĐŚĂŶŝƐŵ͕ ƚŚĂƚ ŵĞĂŶƐ͕
side power terminal. All are arranged in series. If ŵĂLJ ďĞ ĚƵĞ ƚŽ ĚĞĨŽƌŵĂƟŽŶ ŽĨ ďŝ Ͳ ŵĞƚĂůůŝĐ ƐƚƌŝƉ͕
ĐŝƌĐƵŝƚ ŝƐ ŽǀĞƌůŽĂĚĞĚ ĨŽƌ ůŽŶŐ ƟŵĞ͕ ƚŚĞ ďŝ Ͳ ŵĞƚĂůůŝĐ due to increased mmf of trip coil or may due to
strip becomes over heated and deformed. This ŵĂŶƵĂů ŽƉĞƌĂƟŽŶ͕ ĂĐƚƵĂůůLJ ƚŚĞ ƐĂŵĞ ůĂƚĐŚ ƉŽŝŶƚ ŝƐ
ĚĞĨŽƌŵĂƟŽŶ ŽĨ ďŝ ŵĞƚĂůůŝĐ ƐƚƌŝƉ ĐĂƵƐĞƐ͕ ĚŝƐƉůĂĐĞ- displaced and same deformed spring is released,
ment of latch point. The moving contact of the ǁŚŝĐŚ ƵůƟŵĂƚĞůLJ ƌĞƐƉŽŶƐŝďůĞ ĨŽƌ ŵŽǀĞŵĞŶƚ ŽĨ
MCB is so arranged by means of spring pressure, the moving contact. When the the moving con-
ǁŝƚŚ ƚŚŝƐ ůĂƚĐŚ ƉŽŝŶƚ͕ ƚŚĂƚ Ă ůŝƩůĞ ĚŝƐƉůĂĐĞŵĞŶƚ ƚĂĐƚ ƐĞƉĂƌĂƚĞĚ ĨƌŽŵ ĮdžĞĚ ĐŽŶƚĂĐƚ͕ ƚŚĞƌĞ ŵĂLJ ďĞ Ă
of latch causes, release of spring and makes the high chance of arc. This arc then goes up through
moving contact to move for opening the MCB. The ƚŚĞ ĂƌĐ ƌƵŶŶĞƌ ĂŶĚ ĞŶƚĞƌƐ ŝŶƚŽ ĂƌĐ ƐƉůŝƩĞƌƐ ĂŶĚ ŝƐ
current coil or trip coil is placed such a manner, ĮŶĂůůLJ ƋƵĞŶĐŚĞĚ͘ tŚĞŶ ǁĞ ƐǁŝƚĐŚ ŽŶ ĂŶ D ͕ ǁĞ
that during short circuit fault the mmf of that coil ĂĐƚƵĂůůLJ ƌĞƐĞƚ ƚŚĞ ĚŝƐƉůĂĐĞĚ ŽƉĞƌĂƟŶŐ ůĂƚĐŚ ƚŽ ŝƚƐ
causes its plunger to hit the same latch point and ƉƌĞǀŝŽƵƐ ŽŶ ƉŽƐŝƟŽŶ ĂŶĚ ŵĂŬĞ ƚŚĞ D ƌĞĂĚLJ ĨŽƌ
make the latch to be displaced. Hence the MCB ĂŶŽƚŚĞƌ ƐǁŝƚĐŚ Žī Žƌ ƚƌŝƉ ŽƉĞƌĂƟŽŶ͘

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