Functions, components and specifications of moulded case circuit breakers

I. Plastic Case Circuit breaker (MCCB): Function and component description

In today's world, the demand for electricity is increasing. Not only should we be aware of the value of electricity in times of shortage, but we should also ensure that we conserve it in a sensible way. To solve this problem, power controls are being installed to monitor the current. Sometimes, overloads and short circuits can damage the circuit. Low-voltage switchgear is used to protect the circuit during uncertain events. In this article, we will reveal what is a moulded case circuit breaker? And the function, components and specifications of the moulded case circuit breaker.

II. What is MCCB

MCCB is an abbreviation for Plastic-case circuit breaker used to protect circuits and their components from overcurrent. If this current is not isolated at the right time, it will cause an overload or short circuit. These devices have a wide frequency range, which makes them suitable for a variety of applications to protect circuits. They range in current rating from 15 amps to 1600 amps and can be used in low-voltage applications. You can visit our website at www.ace-reare.com. Buy Acereare Electric MCCB at the best price.

III. The function of the plastic case circuit breaker

● Overload protection
● Electrical fault protection
● Open and close the circuit

MCCBS can be disconnected automatically and manually and are significantly used as an alternative to microcircuit breakers in photovoltaic systems. The moulded case circuit breaker is installed in a molded housing to protect it from dust, rain, oil and other chemicals.

Since these devices handle high currents, they require proper maintenance from time to time, which can be done through regular cleaning, lubrication, and testing.

IV. Protect your electrical equipment

All of your electrical equipment needs a steady current to work well. It is important to install the MCCB or MCB according to the load current. By doing so, sophisticated machine control systems can be protected by isolating the power supply during electrical failures.

V. Avoid fire

An MCCB that meets industry standards and is of good quality is recommended to ensure maximum safety. These electromagnetic devices detect faults in the event of a power surge or short circuit to protect them from fire, heat and explosions.

VI. Components and specifications of moulded case circuit breakers

The four main components of a moulded case circuit breaker include
• Shell
• Operating mechanism
• Arc extinguishing system
• Trip device (thermal trip or electromagnetic trip)

SHELL

Also known as the housing, it provides space for the insulated housing to install all circuit breaker components. It is made of thermosetting composite resin (DMC mass material) or glass polyester (injection molded parts) to provide high dielectric strength in its compact design. This name is assigned according to the type and size of the moulded case and is further used to describe the characteristics of the circuit breaker (maximum voltage and rated current).

Operating mechanism

The opening and closing of the contact is accomplished by an operating mechanism. The speed at which the contacts are opened and closed depends on how fast the handle is moving. If the contact trips, you will be able to see that the handle is in the middle position. If the circuit breaker is in the on position, it is impossible to make it trip, which is also called "automatic trip".

When the circuit breaker is tripped, that is, if the handle is in the middle position, it must first be moved to the off position and then to the on position. In cases where circuit breakers are installed in a group (such as a switchboard), different handle positions help to find the faulty circuit.
Usually, before the circuit breaker leaves the factory, we will detect the opening and closing of the circuit breaker overload and short circuit in single-phase and dual-phase ways to monitor whether the circuit breaker is tripped within the set range value to ensure the safety of the circuit breaker in the actual use of the site.

Arc-extinguishing system

Arc interrupter: Arcing occurs when the circuit breaker interrupts the current. The function of the interrupter is to confine and divide the arc, thereby extinguishing it. The arc extinguishing chamber is enclosed in a high-strength insulated box, which is mainly composed of a number of arc extinguishing grid pieces, which play an important role in arc initiation and arc extinguishing in low-voltage electrical products. When the contact splits due to an interruption, the current flowing through the ionized region of the contact creates a magnetic field around the arc and the interrupter.

The magnetic field lines created around the arc drive the arc into the steel plate. The gas is then deionized, separated by an arc, allowing it to cool. Standard MCCBS use a linear current through the contact, which, under short circuit conditions, creates a small burst force, which helps to open the contact.

Most of the opening action is generated by the mechanical energy stored in the tripping mechanism itself. This is because the current in both contacts flows in the same direct current.

Trip device (thermal or electromagnetic trip)

The trip device is the brain of the circuit breaker. The key function of the tripping device is to trip the operating mechanism in the case of short circuit or continuous overload current. Traditional mould-case circuit breakers use electromechanical tripping devices. Circuit breakers are protected by combining temperature sensitive devices with electronic trip devices, which can now provide more advanced protection and monitoring. Most moulded case circuit breakers utilize one or more different trip elements to provide circuit protection for a variety of applications. These tripping elements protect against thermal overloads, short circuits and arc ground failures.

Conventional MCCBS provide fixed or interchangeable electromechanical tripping devices. If a fixed trip circuit breaker requires a new trip rating, the entire circuit breaker must be replaced. Interchangeable trip devices are also called rated plugs. Some circuit breakers provide interchangeability between electromechanical and electronic trip devices in the same frame.

To ensure the efficient operation of the MCCB, regular maintenance should be carried out, including visual inspection, cleaning and testing.

VII. Application of moulded case circuit breaker

The MCCB is designed to handle high currents and is widely used in heavy duty applications such as adjustable trip Settings for low current applications, protection of motors, protection of capacitor banks, welders, protection of generators and feeders.

Specifications of moulded case circuit breaker
•Ue - Rated operating voltage.
•Ui - Rated insulation voltage.
•Uimp - impulse withstand voltage.
•In - nominal rated current.
•Ics - Rated operating short-circuit breaking capability.
•Icu - Rated limit short-circuit segment capacity.