Marine low-voltage switchgear

Marine low-voltage switchgear needs to meet the special requirements of ship application systems, environments, etc., and develop new products through customized design to meet application needs.

The frame circuit breaker adopts a pull-out structure, and the circuit breaker needs to be certified by a classification society. Meet the long-term current test in a 45 degree environment. Connecting copper bars requires reliable connection and vertical arrangement to reduce heat generation. Adding copper bars as heat sinks can effectively dissipate the heat generated inside the circuit breaker and contacts. The insulator supports the busbar, with high strength and meets the IP44 rating, requiring a cover.

For the fixed group molded case circuit breaker output circuit, two different forms are designed according to application requirements. Under high protection level requirements, the switch status can be checked through the glass door and the cabinet door can be opened for operation. For those without waterproof requirements, the operating handle is directly inserted through the door panel to quickly open and close the circuit breaker

The protection level of this type of door panel directly operated molded case circuit breaker can generally reach IP22, meeting the requirements of general ship applications. The top and bottom ventilation holes ensure smooth airflow, and high-density installation of switches will not cause excessive temperature rise.

The basic design of the two forms is consistent, that is, a high-density group circuit breaker layout, such as an 800mm wide switchgear, can be arranged in six rows of circuit breakers on top and bottom, each row can install six plug-in plastic shell circuit breakers, and one switchgear can install a total of 36 circuit breakers, that is, 36 outgoing circuits. The ultra compact layout meets the redundancy backup requirements of ship applications.

For the motor control circuit, it is also necessary to consider the marine application environment. For high protection levels and harsh environmental requirements, the drawer type motor control unit also needs to ensure a high protection level, such as IP44 requirements, at the disconnection and testing positions. For drawer units that are in standby or maintenance state for a long time, if they do not meet the protection requirements, they will become damp and corroded after long-term storage, and cannot continue to be used.

Regardless of whether the drawer is in the compartment or in any position, the compartment door can maintain an IP44 protection level, achieving the purpose of easy maintenance with a pull-out design and ensuring that the main circuit is not affected by the environment.

Although the switchgear does not necessarily require IP44, high salt spray corrosive air is ubiquitous in marine environments. Reducing the exposure time of busbars, contacts, and electronic products to external air, extending equipment life, and improving reliability are crucial. External visualization of drawer position and switch operation status, simple and reliable.

All doors that can be opened are equipped with an open position lock function to avoid equipment collisions caused by accidental shaking during operation and maintenance.

The front and rear handrails of the cabinet are also very important requirements for marine switchgear, and maintenance personnel should always connect them to ensure that they will not be injured due to shaking. Non metallic insulated handrails are required according to standards. Using metal handrails with insulation coating, the coating layer and metal handrails cannot rotate or slide relative to each other, ensuring the safety of operators with attention to detail. The armrest needs to be able to withstand twice the weight of a normal person.

The side panel structure has high strength, and for the durability test of ship vibration, a continuous vibration test of 90 minutes is required at resonance points in all directions. Compared to the beam splicing structure, the side panel structure has fewer connection points and stronger vibration resistance. Experimental results have shown that bolt scattering occurs after the beam assembly structure test, making it difficult to withstand longer durability tests.

Similarly, door locks require resistance to continuous vibration, and features such as nylon anti loosening nuts, anti loosening door locks, and bottom rubber buffers are specifically designed for ship applications.