MCCB is mainly used to provide protection for overload and short circuit in low voltage distribution system and motor protection circuit. Because of its reliability and stability, it has been widely used in industry. Moulded case circuit breaker is also called device circuit breaker. All parts are sealed in plastic shell. Auxiliary contact, undervoltage release and shunt release are mostly modularized. Due to its compact structure, moulded case circuit breaker can hardly be repaired. Most of them are operated by hand, and large capacity can choose electric on-off. Due to the application of electronic over-current release, moulded case circuit breaker can also be divided into class A and class B. class B has good three section protection characteristics, but due to price factors, class a products with thermal magnetic release have a higher market share
Miniature circuit breaker
MCB, short for MCB in English, is a circuit breaker product with a wide range of applications and a large number of applications. Its main function is to provide protection for building electrical terminal distribution devices. Because both of them belong to circuit breaker, and MCCB is mostly used for small capacity on-off.
The miniature circuit breaker is composed of operating mechanism, contact, protection device (various releases), arc extinguishing system, etc. The main contact is manually operated or electrically closed. After the main contact is closed, the free tripping mechanism locks the main contact in the closing position. The coil of the over-current release and the thermal element of the thermal release are connected in series with the main circuit, and the coil of the under voltage release is connected in parallel with the power supply. When the circuit is short-circuit or seriously overloaded, the armature of the over-current release will pull in to make the free release mechanism act, and the main contact will disconnect the main circuit. When the thermal release mechanism on the bimetal is bent, the thermal release mechanism acts freely. When the circuit is under voltage, the armature of the under voltage release is released. It also makes the free release mechanism act.
Difference between MCCB and MCB
Let's talk about the basic similarities first, because both are circuit breakers, they need to comply with some basic product standards and have the same working principle. Next, the difference between the two, generally speaking, there are the following points: 1. Different electrical parameters, 2. Different mechanical parameters, 3. Different working environment. In addition, from the perspective of purchase, the specific differences between the two.
Molded case circuit breaker current level up to 2000a have. The maximum current level of MCB is within 125A. Due to the difference in capacity between the two, the effective area of MCCB is larger than that of MCB in specific work, and the connecting wire is thicker, which can reach more than 35 square meters, while MCB is only suitable for connecting wires less than 10 square meters. So generally for indoor conditions, the larger room is more suitable to choose MCCB.
Molded case circuit breaker is mainly installed with screws, which is easy to press, has good contact and stable operation. The micro circuit breaker is mainly installed through the guide rail, sometimes due to insufficient torque and poor contact. Due to the different installation methods, the installation of MCCB is more stable and less difficult than miniature circuit breaker.
Operation and service life:
In terms of operation. Moulded case circuit breaker adopts two sets of devices to protect over-current and short circuit respectively. The action value of over-current protection can be adjusted manually, which is convenient and rapid. The miniature circuit breaker shares a set of device for over-current and short circuit, and the current is not adjustable, which leads to many problems that can not be solved. Moulded case circuit breaker has large phase to phase distance, and has arc extinguishing cover, strong arc extinguishing ability, can withstand larger short circuit current, and is not easy to cause phase to phase short circuit, so its service life is longer than that of miniature circuit breaker.
Flexibility in use:
In this aspect, MCCB is more prominent, and its setting flexibility is better than MCB. The over-current and short-circuit protection devices of MCCB are independent, and the action value of over-current protection can be adjusted flexibly. The lack of flexibility in the unified short-circuit protection and over-current regulation of the miniature circuit breaker is certain. According to the above situation, it seems that the miniature circuit breaker is at a disadvantage, but in fact, for some times, it is still necessary to choose the miniature circuit breaker.
For example, when we need to improve the safety of the line, because the micro circuit breaker has high sensitivity and fast breaking action, it is more conducive to the protection of the line and electrical appliances. It can be seen that both of them have their own advantages and are suitable for use. The key is to fully understand the difference between MCCB and MCB, and choose according to their own needs.