Why dc supply is used for closing and tripping coil of ht
breakers. What happen if we use only ups ac supply only.

Answer Posted / nishant2110

hey guys ....what a funny answers !!!! we have only two
extreams either open or closed. which can be serve by dc
only ..means if dc is given to trip coil,coil gets
magnetise in one direction.so that breaker gets opened.
Suppose if Ac would have been given two coil,magnetic
direction must gets changed according to frequency of
supply. So breaker starts to-n-fro motion. practically
there wont be any to-n-fro motin also because its frequency
is so high it will stay at same position. so it wont serve
the use of breaker.

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