What is MNS Low-Voltage Draw-out Switchgear

MNS Low-Voltage Draw-out Switchgear

The MNS low-voltage draw-out switchgear is a modulus combined device specially designed for low-voltage power distribution systems, applicable to power networks with an AC frequency of 50-60Hz and a rated operating voltage of 660V and below.

Its core structure is assembled with 25mm modulus C-section steel frames, featuring a three-position design (connected/test/separated) for drawer units and supporting the mixed configuration of 1-3 main units as well as 1/4 and 1/2 sub-units. The total effective installation height of the cabinet reaches 1800mm. The maximum rated current of the horizontal busbar of this equipment can reach 5000A, and the withstand current of the vertical busbar ranges from 900A to 1600A, with a protection grade covering IP30 to IP54 standards.

Its application scenarios include conventional environments such as power plants, industrial and mining enterprises, and municipal construction. After special treatment, it can also be used in extreme environments such as offshore oil platforms and nuclear power plants.

Table of Contents

1. Core Structure

2. Technical Characteristics

3. Environmental Adaptability

4. Typical Applications

5. Innovative Design

6. Quality Control

1. Core Structure (Modular, Modulus E=25mm)

1.1 Cabinet Frame

- Material: Cold-rolled steel C-shaped profiles with 25mm modulus holes, galvanized and powder-sprayed for excellent anti-corrosion performance and reliable grounding.

- Common Dimensions: Height 2200mm, width 400/600/800mm, depth 800/1000mm.

- Partition Design: Independent functional compartment, busbar compartment and cable compartment with safe isolation between each area.

1.2 Functional Units (Core Draw-out Type)

(1) PC Unit (Power Cell, Incoming / Bus Coupler / High-Current Feeder)

- Adopts fixed or draw-out type configuration, equipped with circuit breakers such as Emax for large-current applications.

- Installation Position: Upper or rear part of the cabinet, connected to the main busbar with high breaking capacity.

(2) MCC Unit (Motor Control Center, Drawer-Type Outlet)

- Standard Drawer Sizes: Height 100/150/200mm (4E/6E/8E).

- Functions: Motor control (direct start / star-delta start / soft start), power feeding, lighting and control circuits.

- Three Working Positions: Working (connected), Test (isolated), Draw-out (power off), equipped with mechanical interlocks to prevent misoperation.

(3) Compensation Unit

- Installed with capacitor and reactor sets for reactive power compensation and harmonic suppression.

(4) Metering Unit

- Equipped with PT, CT and electric meters to realize electric energy metering and operational monitoring.

1.3 Busbar System

- Main Busbar: TMY copper bars, horizontally arranged with insulating supports for power distribution.

- Distribution Busbar: Vertically arranged and connected to drawers through plug-in connections for reliable contact performance.

- Grounding System: Complete grounding of cabinet body, frame and drawers to ensure continuous protection performance.

1.4 Protection and Safety

- Protection Grade: Standard IP30, customizable IP40/IP54 for anti-electric shock and foreign object prevention.

- Interlock Devices: Mechanical interlocks for three-position drawers, interlocks between circuit breakers and disconnectors, as well as door and circuit breaker interlocks.

- Insulation Structure: High-strength flame-retardant engineering plastic partitions for arc prevention and accidental touch protection.

2. Technical Characteristics

Optimized design based on ABB technology realizes the assembly of various components through modularization. The drawer unit is equipped with a mechanical interlock device to support fast plugging and unplugging operations. The main circuit plug-in features excellent short-time withstand capacity and high breaking capacity, with superior dynamic and thermal stability. The flexible electrical scheme can meet most power distribution scenarios.

The cabinet adopts a thick C-profile skeleton structure with dual anti-corrosion treatment of cold-rolled steel plate and aluminized zinc plate. The internal functional areas include horizontal busbar compartment, electrical component compartment and cable compartment, which are physically isolated by flame-retardant engineering plastic plates. The standard cabinet features complete modular mixed configuration and strong scene adaptability.

3. Environmental Adaptability

The conventional operating temperature range is no higher than +40℃ and no lower than -5℃ for ambient air temperature, with the average temperature within 24 hours not exceeding +35℃. In terms of humidity conditions, the relative humidity shall not exceed 50% at the maximum temperature of +40℃, and can reach up to 90% at +20℃.

Dual-mode heat dissipation systems are configured for special environments. The air-cooling mode adopts movable heat dissipation plates and activated carbon adsorption nets, while the water-cooling mode adopts coiled water pipes for circulating heat dissipation. The operation mode can be automatically switched according to humidity sensors.

4. Typical Applications

In the power generation field, this equipment serves as a power center cabinet to control large-power motors and is equipped with conventional series circuit breakers. In substation applications, the vertical busbar adopts a double-layer structure design with stable continuous current-carrying performance. For petrochemical industry scenarios, cabinets with IP54 protection grade are selected, and the busbar compartment is coated with acid and alkali resistant paint.

The improved patented model launched in 2024 adds electric telescopic rod synchronous control drawers and rotary filter screen structures, which improves the operational efficiency and reliability in power generation, transmission and distribution scenarios.

5. Innovative Design

The utility model patent (CN215221413U) of Jiangsu Linmai Electric in 2024 realizes multi-drawer linkage operation, with electric telescopic rods controlling the synchronous movement of three groups of fixed plates.

The invention patent (CN114665407A) of Shandong Dingsheng in 2024 includes moisture-proof performance design. The modular drawer structure, dual-mode heat dissipation system and humidity induction trigger mechanism improve the adaptability in humid environments. The linkage device of the cabinet top baffle and water storage tank effectively prevents rainwater backflow, and the bottom flow guide structure improves drainage efficiency.

6. Quality Control

The product has obtained CCC certification and implements the GB7251.1-2005 standard in the production process. The factory test includes 2500V/1min dielectric strength test.

The transportation specification limits the single shipment quantity to no more than 4 units, and the hoisting vertical deviation shall be less than 15 degrees. During commissioning, more than three drawer plugging tests are required to ensure qualified contact resistance of contacts.

Summary

The MNS switchgear is a high-end low-voltage complete equipment with modular design, draw-out structure, high safety, convenient maintenance and intelligent expandability. Featuring reliable structure, stable power supply and flexible maintenance, it has become the preferred mainstream equipment for low-voltage power distribution systems in industrial and key construction projects.