01-06-2012, 04:49 PM
ULTRA FAST ACTING ELECTRONIC CIRCUIT BREAKER
11 Electrinic circuit breaker.pdf (Size: 192.3 KB / Downloads: 199)
ABSTRACT
The outline of the project is to shut down the power supply when it is overloaded. Conventional circuit breaker is based on thermal bimetal lever trip mechanism, which is very slow and the trip time is dependant upon the percentage of overload. So, Electronic circuit breaker is designed which is based on the voltage drop across a series element typically a low value resistor or a CT (current Transformer). The voltage sensed is compared against the preset voltage proportional to the current by a level comparator to generate an output for the Relay or contactor to trip the load. The unit is extremely fast and overcomes the drawback of the thermal type. It uses an 8-bit microcontroller from 8051 family into which program is burned for the operation of this project. The power supply consists of a step down transformer 230/12V, which steps down the voltage to 12V AC. This is converted to DC using a Bridge rectifier. The ripples are removed using a capacitive filter and it is then regulated to +5V using a voltage regulator 7805 which is required for the operation of the microcontroller and other components.