The
project is designed to shut down the power supply when it is overloaded.
Conventional circuit breaker like MCB based is on thermal bimetal lever trip
mechanism. It is very slow and the trip time is dependent upon the percentage
of overload.
This
project senses the current passing through a series element and the
corresponding voltage drop is compared against the preset voltage proportional
to the current by a level comparator to generate an output for the load to
trip.
The
concept of electronic circuit breaker came into focus realizing that
conventional circuit breakers such as MCBs take longer time to trip. Therefore,
for sensitive loads it is very important to activate the tripping mechanism at
the shortest possible time, preferably instantaneously.
This
project is demonstrates fast tripping mechanism as against the slow one like
MCB. Electronic circuit breaker is based on the voltage drop across a series
element proportional to the load current, typically a low value resistor.
This
voltage is sensed and rectified to DC which is and then compared with a preset
voltage by a level comparator to generate an output that drives a relay through
a MOSFET to trip the load. The unit is extremely fast and overcomes the
drawback of the thermal type. It uses a microcontroller from 8051 family.
Further
the project can be enhanced by using a CT for galvanic isolation between mains
and control circuit. Power electronic devices such as thyristors / IGBTs can be
used for ultra fast operation compared to all the methods.
Interesting Topic
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