Explain the principle of operation of attracted armature relay with equation and characteristics curve.

Explain the principle of operation of attracted armature relay with equation and characteristics curve.
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1 Answer

Answer :

Principle: It works on the principle that when a current is passed through a coil magnetic lines of force develop and the coil behaves like a magnet. When we place a magnetic material inside the coil it is attracted.

In attracted armature type of relays there is a spring that keeps the contact open, a plunger that tends to close the contact and a coil through which current is passed. The spring force and magnetic force oppose each other. When these both are equal the relay will pickups. 

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We can see the inverse characteristics from the above formulae. Usually attracted armature relays are instantaneous. That is there is no intentional (fixed) time delay. If we want a time delay we can add a slug in the armature core.  

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