There are two major types of breakers, the electrical and mechanical. Electrical breakers require an electric starting handle and a grounded wire to work. The starting point for the electric starting handle is usually a small switch on the wall.
The electrical breakers work off of the principle of opening and closing circuits. An electrical starting handle creates a voltage that the circuit broken, and the door closes when this voltage is equal to or greater than the starting point.
The circuit breaker design is dependent on high currents and varies to avoid arcing during operation. There are several ways to classify circuit breakers. The most common method for classifying a circuit breaker is from the middle of the end of the arc. The arc can easily be eliminated by various media such as air, insulator, gas, vacuum, dielectric, etc.
There are various advantages associated with the use of circuit breakers. Firstly, they reduce the chances of an electric shock or fire happening in an office or any building. Second, they protect against spikes in voltage that can damage electrical equipment and appliances. Finally, they prevent injury and protect property when there are shorts in the wiring system. This makes them highly preferred by businesses.
What is Circuit Breaker?
A Circuit Breaker is a switching device that used automatically and manually to protect and controlled electrical systems or electrical circuits. If overheated or over current the electrical wiring system can cause fires, power outages, and explosions. But before such dangerous reactions can occur, the circuit breakers turn off the electricity and continue to operate.
While modern power systems operate with very high currents. Special care must take when designing a circuit breaker to ensure that it can safely block the arc that occurs when the circuit breaker tripped. It is the basic definition of a circuit breaker.
They operate without interruption as long as the equipment is powerful enough to withstand current or voltage. Causes of heating wires are too much charge flowing through the circuit, or a short circuit, or a good connection of the hot wire to the ground wire, heats up the wires, causing a fire. Circuit breakers prevent situations that will easily disconnect the rest of the circuit.
It is an automatic, self-operative electric switch installed in Electrical Controllers, Fuses, and Components to prevent excessive current from a short circuit or extreme overload from an electric shock. Its primary function is to stop the current flow once a fault identified. It does this by cutting off the current just before it breaks the circuit, disconnecting the circuit permanently.
For low voltage circuit breakers, this usually done inside the device itself. The heating or magnetic effects of electric current commonly used. Circuit breakers for high currents or high voltages are generally equipped with protective relay pilots to detect the fault condition and actuate the tripping mechanism.
Usually require a separate power source such as a battery, although some HV circuit breakers are self-contained with current transformers, protective relays, and an internal control power supply.
Classified types of Circuit Breakers
There are many different types of circuit breakers available in the market. Depending on the need and requirements, they can be classified into five categories based on the load capacity that they can handle. Some examples of such categories are thermal, magnetic, electrostatic, and media-based breaker.
This article provides some basic information about each type of circuit breaker. If you wish to buy any circuit breaker, it is always better to go through this article to understand every aspect of it. Circuit Breakers are divided into three types according to category. which is describe below
1: Low Voltages Circuit Breakers
2: Medium Voltages Circuit Breakers
3: High Voltages Circuit Breakers
1: Types of Low Voltages Circuit Breakers
A circuit breaker is an equipment or a device that can open or close, no-load, full-load, and fault conditions. The main function is to isolate parts of the power distribution system even under abnormal conditions.
It is designed in such a way that it can be operated manually or by remote control under normal conditions and automatically in the event of a malfunction. In addition to providing system protection, circuit breakers can isolate parts of the distribution network for operation and maintenance.
1. MCB Miniature Circuit Breaker
A Miniature circuit breaker (MCB) is a circuit breaker used to protect low voltage electrical circuits from damage caused by overcurrent due to overload or short circuits. The circuit breakers are designed for currents up to 125 A, do not have adjustable tripping characteristics, and can operate as thermal or thermomagnetic.
An MCB is much more sensitive to overcurrent than a fuse. Handling MCBs is electrically safer than fuses. Rapid recovery of power is possible in a blown fuse, as the fuses must be reconnected or replaced to restore power. Recovery is easily possible just by turning it on.
MCB is very simple, easy to use, and usually not repairable. It’s just easier to replace. The release is the main part responsible for its correct operation. There are two main types of shutdown mechanisms. The bimetal provides protection against overload current, and the electromagnet provides protection against short-circuit current.
2: MCCB Molded Case Circuit Breaker
The MCCB Molded case circuit breaker is an electrical protection device that can be used over a wide range of voltages, currents, and frequencies. It is a protective device that is used when the load currents exceed the capacity of the circuit breakers.
It can also be used in rated current applications where an adjustable trip setting is required that is not available with plug-in circuit breakers or miniature circuit breakers. The main difference between a molded case circuit breaker and a miniature circuit breaker is that the circuit breaker can be rated up to 2500 amps. Its trip settings are usually adjustable.
An additional difference is that the MCCB is usually much larger than the MCB.
The wide range of current ratings of molded case circuit breakers allows them to be used in various applications. Circuit breakers are available with current ratings ranging from low ratings such as 30 amps to industrial ratings such as 2500 amps.
A thermal mechanism provides overload protection. Molded case circuit breakers have a bimetallic contact that expands and contracts as the temperature changes. Under normal conditions, the contact will pass electrical current through the circuit breaker.
However, once the current exceeds the average rating, the contact will heat up and expand until the circuit is interrupted. This thermal overload fuse is designed with a time lag to withstand the transient overcurrent conditions in many devices. However, if the overcurrent lasts longer than expected, the circuit breaker will trip to protect the equipment.
3: RCCB Residual Current Circuit Breakers
RCCB Residual Current Circuit Breaker is an important measure when it comes to protecting electrical circuits. It is a current sensing component that can automatically measure and disconnect a circuit when a fault occurs in the connected circuit, or the current exceeds the rated sensitivity.
A Residual current circuit breaker is essentially a device that measures current and disconnects any low voltage (unbalanced current) circuit whenever any fault occurs. There are several types of circuit breakers, such as the MCCB, which work according to different operating principles and have different safety goals.
A residual current circuit breaker mainly installed to protect a person from shock or death caused by shock. It prevents accidents by shutting down the main circuit in a fraction of a second. The RCCB is the device for detecting and disconnecting from leakage currents. Which provides protection against electric shock caused by indirect contacts.
These devices must be used in series with a circuit breaker or fuse that protects them against potentially damaging thermal and dynamic loads from any overcurrents. They also act as main switch-disconnectors in front of any derived circuit breakers (e.g. household consumer).
Its work based on Kirchhoff’s current law, that is, the incoming current in a circuit must be equal to the output current from this circuit. This circuit breaker designed so that whenever a fault occurs. The current balance of the line and neutral do not match (imbalance occurs).
Its circuit is made so that in each case, the value of the incoming and outgoing current of the circuit compared. When not equal, the residual current, which is the difference between the two currents, drives the trip/trip circuit.
2: Types of Medium Voltages Circuit Breakers
Medium voltage circuit breakers help monitor medium voltage and use protection relays to check for any dangerous deviations. They are typically used for voltages between 1000 and 72000 volts. They can also be installed for both indoor and outdoor use.
Medium voltage switches are switches that operate at voltage levels from 400 volts to 72 kV. They are so named because extremely low voltage conditions are not suitable for their proper operation, and very high voltage does not help them do their job accurately.
One difference between medium voltage circuit breakers is that they can be operated manually or automatically, unlike most types of these circuit breakers.
1: ACB Air Circuit Breakers
Air circuit breakers ACB are the most common type of medium voltage circuit breakers used in industrial environments due to the age of the equipment and the low cost. ACB is an electrical device used to provide overcurrent and short-circuit protection for electrical circuits from 800 amperes to 10 k Ampere.
ACB breakers operate with their contacts in the open air. Their method of controlling arc extinction is completely different from that of oil circuit breakers. They have always been used for low voltage interruption and are now replacing high voltage oil circuit breakers. The figure below shows the operating principle of the air circuit breaker circuit.
The main contact assembly is mounted on a contact arm that pivots to open or close the main contacts using a spring-loaded operating mechanism triggered via trip or closing coils using a control switch or protective relay. The ability to interrupt the current air circuit breakers depends on their ability to extinguish an arc that occurs when the main contacts of the circuit breaker open or close.
2: VCB Vacuum Circuit Breakers
A vacuum circuit breaker is a type of circuit breaker with an arc quenching in a vacuum medium. Closing and closing the interference between live contacts and the interconnection occurs in a vacuum chamber in a circuit breaker called a vacuum circuit breaker.
The arc disappeared because there is more space between the contacts. It is mainly used for medium voltage from 11 kV to 36 kV. A vacuum circuit breaker is a type of circuit breaker used to extinguish an electric arc in space. This breaker is suitable for medium voltage applications.
Vacuum technology was developed for high voltages but is not commercially viable. The process of opening and closing the current-carrying contacts and the corresponding arc barrier occurs in the vacuum chamber of the circuit breaker, called the vacuum interceptor.
The center of the vacuum interrupter consists of a steel arc chamber in ceramic slotted arc insulators. The vacuum pressure inside the vacuum interceptor is usually kept at 6 to 10 bar.
3: Types of High Voltages Circuit Breakers
A circuit breaker is an electrical switching device used to protect and control an electrical system that can be operated manually or automatically. Mechanical energy for opening most high voltage circuit breakers is provided by a charged spring. The spring is usually used by the gear mechanism from the DC motor and it also has the ability to charge the spring manually.
The spring is released through a mechanism that is activated by an on or off coil for proper operation. These coils are linear solenoid actuators used to supply electrical signals. During both manual and automatic operations, a control signal must be applied to the coils.
1: Oil Circuit Breakers
An Oil circuit breaker is a type of circuit breaker in which oil is used as a dielectric or insulating to eliminate the arc. The switch contacts in the oil switch designed to separate the insulated oil inside. Mineral oil has better insulating equipment than air. In an oil circuit breaker, the fixed contact and the dynamic contact are immersed in insulating oil.
Whenever there is a separation of current-carrying contacts in the oil, an arc of the circuit’s opening begins at the moment of separation of these contacts. Because of this arc, the oil evaporates and melts with most hydrogen gas and, ultimately, hydrogen.
This high-pressure gas bubble around the arc prevents the arc from re-entering when it reaches zero crossings. Oil circuit breakers are one of the oldest types of circuit breakers. When a system failure occurs, the breaker contacts open under the insulating oil, and an arc is formed between them, and the heat of the arc evaporated into the surrounding oil. The switchgear has fixed and dynamic connections that help protect the circuit in substations and transformers.
2: Sf6 Gas Circuit Breakers
Sf6 Gas Circuit Breakers or Sulfur hexafluoride circuit breakers protect power plants, girds, and distribution systems by interrupting electrical currents when disconnected from safety relays. SF6 circuit breakers are widely used in electrical girds with transmission voltages up to 800 kV, as generator circuit breakers, and in distribution networks with voltages up to 132 kV.
The SF6 circuit breaker is an extinguisher that uses gaseous sulfur hexafluoride to cool and extinguish the arc. In high voltage circuit breakers such as SF6, a current barrier is created by separating the contacts in a gaseous atmosphere.
The separation of the moving contacts carried out using an opening valve. Which allows SF6 gas at a high pressure of 14 kg/cm to attack and extinguish the arc. When an error occurs, the dynamic contacts are disconnected and an arc is created between them.
Since SF6 gas is electric and loves free electrons, it absorbs free electrons to form non-negative ions. The SF6 circuit breaker uses SF6 gas (sulfur hexafluoride) as a fire extinguisher. This gas is electronegative and has a high dielectric strength to absorb free electrons.
It has closed movable and fixed contacts in a chamber called an arc barrier chamber filled with SF6 gas. The connection is made to the SF6 gas tank. The valve mechanism allows gas to flow from the reservoir into the arc barrier chamber.