Working principle of MCB; Miniature arc circuit breaker

MCBs or Miniature Circuit Breakers are electromechanical devices which protect an electrical circuit from an over-current. 

Where Miniature circuit breaker means minimum arc circuit breakers.

The over-current, in an electrical circuit, may result from short circuit, overload or faulty design. A MCB is a better alternative other than Fuse since it does not require replacement once an overload is detected. Unlike fuse, an MCB can be easily reset and thus offers improved operational safety and greater convenience without incurring large operating cost.

MCB is most widely used for industrial and domestic applications i.e. for lighting loads and small motor loads.

MCB or Miniature Circuit Breakers
The working principal of MCB is simple. An MCB functions by interrupting the continuity of electrical flow through the circuit once a fault is detected. In simple terms MCB is a switch which automatically turns off when the current flowing through it passes the maximum allowable limit. Generally MCB are designed to protect against over current and over temperature faults.

There are two contacts one is fixed and the other moveable. When the current exceeds the predefined limit a solenoid forces the moveable contact to open (i.e., disconnect from the fixed contact) and the MCB turns off thereby stopping the current to flow in the circuit. In order to restart the flow of current the MCB is manually turned on. This mechanism is used to protect from the faults arising due to over current or over load.

To protect against fault arising due to over heating or increase in temperature a bi-metallic strip is used. MCBs are generally designed to trip within 2.5 millisecond when an over current fault arises. In case of temperature rise or over heating it may take 2 seconds to 2 minutes for the MCB to trip.

This article covers the insight of a single pole MCB commonly used in the house hold. The following image shows the different internal parts of an MCB with top casing removed. The subsequent sections will examine each part and its function.

Internal Parts of MCB

Internal parts of MCB is as shown below:-


Above pic is self explanatory and very helping in understanding working principle of MCB.




Comments

Post a Comment

Popular posts from this blog

A2XWY; A2XFY Cables meaning; XLPE cables advantages over PVC cables

Technical Specification of Aluminum Cables in terms of codes So many times you have seen coding while specifying cables technical such as A2XWY now what does this means. Now there is nomenclature for the same which is used while describing the same. Where A -  Aluminium 2X- XLPE Insulation W – Steel round wire armour F- Steel Strip Armour WW- Double Steel round Armour FF- Double Steel Strip Armour Y- PVC outer Sheath Wa- Non Magnetic round wire Armour Fa- Non Magnetic Strip Armour AW- Aluminum Wire Armour Now As per A2XWY – This describes that it is Aluminum cable, XLPE insulated, With Steel round wire armour and having PVC outer Sheath. This coding is as per IS 7098(Part1):1988. You have also seen that there is coding for copper so there is no coding required in case of copper cables. XLPE cables advantages over PVC cables/ Thermoplastic cables:- 1.       XLPE cables have higher Power rating about 1.2 times PVC cables 2.       XLPE cables have higher short circuit rating about 1.2 ti
Read more

Wireless voltmeter using Arduino and RF 433MHz receiver and transmitter

Image
In this project i showed you how to make a wireless voltmeter using arduino and RF 433MHz receiver and transmitter. You can use this code and concept for many other projects, any project which used sensor with analog voltage output to sense temperature, gas leakage or light , etc. For example you can put a LM35 temperature sensor rather than potantiometer, you just have to putting its formula which convert LM35 output pin voltage to exact temperature. You also can make a wireless AC or DC power meter by doing some change in code and hardware (using hall effect current sensor and single phase voltage sensor). This type of RF module has distance range up to 200 meters according to datasheet but when i bought this RF module from Aliexpress its distance rang was very low, but i set its adjustable RF coil very carefully and i get very higher distance rang.(Don't play with RF coil if your module works good), You also have to use a 6 inch antenna to increase distance range to max as possi
Read more

Story beyond the "Transistor"

Image
            John Bardeen, a inventor of the transistor that led to modern electronics and twice a winner of the Nobel Prize in Physics, died yesterday at Brigham and Women's Hospital in Boston. He was 82 years old.                                    Dr. Bardeen, a professor emeritus at the University of Illinois at Urbana-Champaign, was a patient at the hospital when he suffered a heart attack, said Larry Bernard, a university spokesman. A soft-spoken theoretical physicist, Dr. Bardeen was working with two other scientists, Walter Brattain and William P. Shockley, at the American Telephone and Telegraph Company's Bell Laboratories in Murray Hill, N.J., when they developed the first semiconductor transistor in 1947. The invention was announced in June 1948, and its first commercial use was in telephone-switching equipment four years later. Revolutionary Inventions. Invention of the transistor earned the three men a Nobel Prize in 1956 and transformed science and industry. The ti
Read more