Ultra Fast Acting Electronic Circuit Breaker

  • Ultra Fast Acting Electronic Circuit Breaker

Ultra Fast Acting Electronic Circuit Breaker

Product Description

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.

Project Highlights

  • Easy to use, Self-explanatory kit.
  • All-inclusive solution kit.
  • Extensive audio-visuals available.
  • Branding-free material.
  • Pre-programmed Microcontroller.
  • Current Sensing.
  • Call/mail for Tech Support from 10 am - 7 pm.

Block Diagram

Hardware Requirements

  • 8051 series Microcontroller
  • Op-amp
  • Transformer
  • Diodes
  • Capacitors
  • Resistors
  • LED
  • Crystal
  • LCD
  • Voltage Regulator
  • Relay
  • Lamps

Software Requirements

  • Keil compiler
  • Languages: Embedded C or Assembly

User Reviews


"I live in Hyderabad, a place that is known for engineering colleges. Went with frnd and bought a set from Ameerpet(tht hs rdymade stuff like this) and it failed just b4 viva. Thats when we got this thx to a senior who is sorta like a geek.. and let me tell u.. Its one reason why me and my frnds got thru the final sem. Works great and is useful too later.. "

Ravi Teja
Order No: HYF1290

"A must-buy. It helped me practice in real time and learn how to make a project by looking at an actual workable unit. (fyi - you get a fully built unit and another full set of components to build another by yourself) so it was great value for us. We shared the costs by 3 (our team for the project) but i got to keep my unit as the other two kept the original. Showed it for my on-campus and got thru too becuase it not just looked neat and profesionally bt worked great later. (still have it in my room, now working with GE in Bangalore) "

Order No: BLR2933

"We have used it for our institution - it is available in lab and has been good for explaining various models in live during class. Strongly suggest every college dept to have it for labs as it is working well - even with regular use at lab for more than 1 year. Note:We got the unit complementarity before launch in 2014 and have later purchased few batches. The team behind it is professional and know what electronics students need and i am writing this review on their request on 13/05/2016"

Mr. Ramesh Kumar Jha
Order No: BQF3698


Q:  What is the difference between Electronic circuit breaker and normal circuit breaker?

A:  Normal circuit breaker is dependent on thermal bimetal lever trip mechanism, whereas Electronic circuit breaker is formed using current sensing element and comparators

Q:  What is the role of microcontroller in this project?

A:  The microcontroller is programmed to display the circuit breaker conditions.

Q:  Will it auto return after fault (overload) clearance?

A:  No, one has to restart the device, as it would toggle between on and off till overload condition is cleared.

Q:  Which microcontroller is used in this project?

A:  A 40 pin microcontroller from 8051 family is used in this project.

Q:  Does this project works for short circuit faults or is only designed to protect against over load?

A:  It works for both fault and over load.

Q:  Up to which rating (load current) we can use this project without modification?

A:  The load adjusted is for 100 watt run and 125 watt trip.

Q:  If we want to use this project for higher rating (more than 5A) what are the modifications needed?

A:  Higher load modifications are possible by use of CT.

Q:  We used 1st lamp as rated load, 2nd lamp as over load. When 1st lamp (rated load) is on, measured value is 4.7V. But we fixed reference value more than 4.7V (say 6V). Why do we want to fix reference value more than measured value?

A:  This is well explained in the documentation provided with project. As long as the relay is not on, the load is on. Thus for the relay not to be on, the output of the comparator has to be logic zero thus drive to the MOSFET gate is zero. For the output to be logic zero the inverting voltage (-) has to be greater than non-inverting (+). Therefore the fixed value at (-) is adjusted in such a way that it is greater than (+), the measured value in single load, resulting in output of the comparator at zero.

Q:  What is the function of MOSFET in this project? Can we use BJT instead of MOSFET?

A:  Here, MOSFET is used as a switch. BJT can be used, but that needs drive current and not voltage as required for MOSFET.

Q:  What is the formula for calculating smoothing capacitor value?

A:  There is some approximated formula .Peak to peak ripple voltage = Load current in amps / (2*line frequency in hertz *capacitance in farads). But as rule of thumb for 1 A current 1000uF is best. Thus it is load dependent.

Q:  For the Potential Transformer, what rating of transformer did you use?

A:  230 volt to 12 volt 0.5 A ( 500mA) transformer is used.

Q:  Is Current Transformer use possible as it has own specific type of transformer?

A:  The CT desired for real time use can be done but cost would be highly unaffordable.

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