Product Overview:
The DC Molded Case Circuit Breaker (MCCB) is designed for efficient and reliable protection of DC electrical systems. It is used to provide overcurrent, short circuit, and under-voltage protection, ensuring the safety and stability of DC power distribution networks.
Structural Features:
Installation Method:
Applicable Environmental Conditions:
The DC MCCB ensures reliable protection and optimal performance in DC power distribution systems, making it an essential component for various industrial and commercial applications.
There are two types of breaking capacity indicators of circuit breakers: rated limit short-circuit breaking capacity Icu and rated operating short-circuit breaking capacity Ics. Ics, as a characteristic parameter, does not simply consider the breaking capacity of the circuit breaker, but as a breaking indicator, that is, after breaking several short circuit faults, it can ensure its normal operation. For plastic-case circuit breakers, there should be enough Icu to break the short-circuit current and make the switch trip. According to the regulations, the Ics of the moulded case circuit breaker is more than 25%Icu is qualified. At present, most of the Ics of circuit breakers on the market are between (50%-75%)Icu, so the power distribution system with low power supply requirements only needs to consider Icu.
When the circuit breaker is short-circuited, the contact quickly opens to generate an arc, which is equivalent to a rapidly increasing arc resistance in the line, thus limiting the increase of the fault current. The less time the circuit breaker is broken, the closer the Ics is to the Icu, the better the current limiting effect, and the adverse effects of the electromagnetic effect, electric effect and thermal effect caused by the short circuit current on the circuit breaker and electrical equipment can be greatly reduced, and the service life of the circuit breaker can be extended.
Short circuit protection is short circuit instantaneous trip. It is necessary to pay attention to adjusting the setting value of the protection in time after the load change to prevent the setting value from being too small and frequent tripping to affect the power supply quality, or the setting value is too small to prevent the line and equipment from being effectively protected.
Overload delay protection means that the load current exceeds the limited range of the equipment and there is a risk of burning the equipment, and the protection device can cut off the power supply within a certain time. There is a process of heat accumulation, and the protection action does not need to be too rapid. For short periods of overcurrent, the protection should not operate.
The isolation function requires that the leakage current after the circuit breaker is turned off will not cause harm to the person and equipment. After multiple short-circuit trips, the performance of the switch decreases and the leakage current increases. For the human body, the leakage current below 30mA is safe, and in a harsh environment, the leakage current of more than 300mA lasts for more than 2 hours, which may cause the insulation damage to occur phase short circuit and then cause a fire.
There are two kinds of leakage apparatus: thermal-magnetic type and electronic type. Compared with electronic type, it has the advantages of small size, high precision and high sensitivity, but its anti-interference ability is poor. At present, the electronic leakage protector occupies the mainstream. When the leakage current reaches the setting value, the executive circuit receives the induced voltage signal on the secondary side of the zero-sequence current transformer, drives the conversion contact to output the leakage protection signal, and makes the trip device act to cut off the power supply.
Generally, the setting leakage trip current of the terminal switch is 30mA, and the setting value of the upper branch switch is 300mA. The arc short circuit with high fire risk is difficult to be effectively cut off by short circuit protection, and the leakage device can reliably disconnect the ground fault to prevent the occurrence of personal electric shock and phase short circuit fault.
2. Second, beautiful appearanceCompared with the traditional air switch, the plastic-case circuit breaker has a more beautiful appearance and can adapt to the decoration and beautification needs of different environments. Its shell adopts engineering plastic structure, gorgeous color, simple and generous appearance, which can meet the aesthetic needs of different customers and improve the grade sense of products and market competitiveness.
1. Low power circuit
Plastic-case circuit breakers are suitable for low-power circuits. In the low-power circuit, the load current is relatively small, the use of plastic-case circuit breaker can effectively reduce the cost, but also will not affect the normal use of the circuit.
2. Home circuits
The load current of the home circuit is relatively small, generally not more than 20 amps. Therefore, the use of plastic-case circuit breakers can meet the needs of home circuits, and can also ensure the safety of the circuit.
3. Low-voltage electrical appliances
Low-voltage electrical appliances generally have high environmental requirements, and need to have certain dustproof, waterproof, corrosion resistance and other characteristics. Therefore, the selection of plastic-case circuit breaker is a more suitable choice.
4. Other areas
In addition to the above areas, plastic-case circuit breakers are also suitable for some other areas, such as smart home, security systems and other fields. In these areas, plastic-case circuit breakers can not only provide power protection, but also bring a more intelligent and convenient use experience.
Plastic-case circuit breaker and air switch are two different types of electrical protection equipment, and they have obvious differences in design, function and application scenarios.
Design differences: Plastic-case circuit breakers use plastic insulators as the housing of the device to isolate conductors and ground metal parts. This design makes the circuit breaker suitable for a variety of environmental conditions, including a wide temperature range and altitude. In contrast, air switches (also known as miniature circuit breakers or miniature circuit breakers) have a simple design, a relatively small current, and are usually used more widely in home lines.
Functional differences: Plastic-case circuit breakers usually contain thermal magnetic trip units, and large-size plastic-case circuit breakers will be equipped with solid-state trip sensors. The trip unit of plastic-case circuit breaker is divided into thermal magnetic trip and electronic trip, which is suitable for large current and is mostly used in industrial distribution cabinets and substations. The air switch is mainly used for overload short-circuit protection, and the current is relatively small, generally not more than 63A, which is suitable for household common circuits.
Difference in application scenarios: Because it can pass a large current (not more than 600A), plastic-case circuit breakers are usually used as low-voltage main switches, which are more common in industrial distribution and substation. The air switch, due to its smaller current carrying capacity, is more suitable for home circuits to provide basic overload and short circuit protection.
In summary, the main difference between plastic-case circuit breakers and air switches is their design, function and application scenarios. Plastic-case circuit breakers are more complex in design and can handle larger currents for industrial and commercial applications. The air switch design is simple, the current is small, mainly used in home circuits.
DC MCCBs come in various ratings, typically ranging from a few amperes up to several hundred amperes. The specific rating needed depends on the application and the current requirements of the electrical system.
To choose the right DC MCCB, consider factors such as the voltage and current ratings, breaking capacity, environmental conditions, and the specific requirements of your electrical system. Consulting with a professional or referring to the manufacturer’s guidelines can also help in making the right selection.
