The MNS series of low-voltage withdrawable switch cabinets are standard, modular, and highly reliable low-voltage complete power distribution devices that have been imported and domesticated. They are suitable for power distribution systems with a three-phase AC 50/60Hz, rated working voltage of 660V or below. They are widely used in power generation, transmission, distribution, power conversion, and power consumption control, and are one of the most widely used low-voltage cabinet types in the industrial and civil fields at present.
I. Application Scope
Rated Voltage: 380V / 400V / 660V
Rated Frequency: 50Hz / 60Hz
Rated Current:
Horizontal busbar: 1000A～6300A
Vertical busbar: 630A～1600A
Feeding / Control circuit: 1A～630A
Applicable Scenarios: Power plants, substations, photovoltaic / wind power stations, petrochemicals, industrial and mining enterprises, high-rise buildings, data centers, hospitals, rail transit, municipal engineering, etc., where high continuity and reliability of power supply are required.
II. Main Technical Parameters
Rated Insulation Voltage: 1000V
Rated Working Voltage: 400V / 690V
Rated Short-time Withstand Current: 30kA～100kA (1s)
Rated Peak Withstand Current: 63kA～250kA
Protection Grade: IP30, IP40, IP54 (as needed)
Busbar System: Three-phase five-wire system / Three-phase four-wire system
Mechanical Life: Drawer unit ≥ 500 times
III. Structural Characteristics
1. Combined Modular Structure
The cabinet body is assembled using C-shaped profile frames, which are strong, highly versatile, and can be freely combined and expanded according to the number of circuits.
2. Clear Function Divisions
The entire cabinet is strictly divided into:
Horizontal busbar room
Vertical busbar room
Function unit room
Cable room
Secondary control small room
Each compartment is isolated from each other, making fault arcs difficult to spread, and the safety is high.
3. Withdrawal-type Drawer Unit Circuits Adopt Standardized Drawer Units, with three positions for connection, testing, and separation, having strong interchangeability, and maintenance can be carried out without power interruption by directly replacing the drawer without affecting the operation of other circuits.
Common Units:
1/2 unit, 1 unit, 2 units, etc., multiple specifications
Can be configured with circuit breakers, contactors, soft starters, frequency converters, dual power supplies, etc.
4. Complete Mechanical Interlocks
There are reliable interlocks between the drawer and the compartment to prevent load insertion and unplugging, and to prevent incorrect operation, ensuring the safety of personnel and equipment.
5. Optimized Busbar System
The main busbar and branch busbars use tin-plated copper strips, featuring low contact resistance, low temperature rise, and strong electrical stress resistance, making them suitable for systems with large currents and high short-circuit strength.
IV. Performance Advantages
1. High space utilization, compact design, with a small floor area for the same capacity, high circuit density.
2. High reliability, convenient maintenance, the drawer can be quickly replaced, suitable for important loads and scenarios where no power outage is allowed for a long time.
3. Strong versatility, flexible configuration, can be composed of power distribution, motor control center (MCC), reactive power compensation, dual power supply switching, PLC control, etc., multiple schemes.
4. Convenient intelligent expansion, can be equipped with intelligent instruments, multi-functional meters, communication modules, arc protection, etc., supporting communication protocols such as Modbus, Profibus, IEC 61850.
5. Good environmental adaptability, can operate stably in indoor conventional environments, slightly corrosive environments, and high humidity environments.
V. Typical Application Schemes
Power Distribution Center (PC Cabinet): Large current incoming line, bus tie, feeding
Motor Control Center (MCC Cabinet): Motor start-up, protection, control
Reactive Power Compensation Cabinet: Automatic switching of capacitors / reactors compensation
Dual Power Supply Automatic Transfer Cabinet: Uninterrupted power supply for important loads
Photovoltaic / Wind Power Low-voltage Grid-connected Cabinet: Current collection, grid connection, islanding protection
VI. Summary The MNS low-voltage withdrawable switchgear features modular design, high reliability, easy maintenance, and strong scalability. It is the mainstream type of low-voltage distribution cabinets in modern power systems, and is particularly suitable for industrial and large-scale construction projects that have high requirements for power supply safety, continuity, and intelligence.