Rated operating voltage (Ue): AC 400V, 690V (commonly used 400V system).
Rated insulation voltage (Ui): AC 1000V.
Rated frequency: 50/60Hz.
Rated current (In):
Horizontal bus: 630A, 800A, 1000A, 1250A, 1600A, 2000A, 2500A, 3150A, 4000A, 5000A, 6300A.
Vertical bus: usually 1000A (standard configuration), optional 1600A, etc.
Drawer unit: 16A, 32A, 63A, 100A, 160A, 250A, 400A, 630A, 800A, 1000A (Type 3 drawer or fixed unit).
Rated short-time withstand current (Icw):
Horizontal busbar (1s): 50kA, 65kA, 80kA, 100kA (common high level).
Vertical busbar (1s): 50kA, 65kA, 80kA (common).
(depends on design and busbar specifications).
Rated peak withstand current (Ipk): Typically 2.1 - 2.2 times Icw (when cosφ=0.5).
Power frequency withstand voltage:
Main circuit: 3500V (1min) / 4200V (1s).
Auxiliary circuit: 2000V (1min).
Protection grade (IP):
Cabinet: IP30, IP40, IP41, IP42, IP54 (common and can reach higher).
Functional unit door closed: IP54 (a significant advantage of MNS, strong dust and water resistance).
Functional unit door open: IP20.
Drawer unit mechanical life: ≥ 2000 - 5000 plug-in and pull-out operations (higher for high-quality products).
Dimensions (width x depth x height):
Width: 600mm (common single-sided operation), 800mm / 1000mm (common double-sided operation/high current).
Depth: 800mm, 1000mm (most common), also 600mm, 1200mm, etc.
Height: 2200mm (standard), also 1800mm, 2000mm or higher.
Temperature rise: in accordance with IEC 61439-1/GB 7251.1 standards, the temperature rise limit of key connection points is ≤70K (such as busbar joints).
Module (E): Basic module E = 25mm.
Cabinet structure: It is composed of standard functional compartment modules (modular units) in height and depth. The cabinet frame adopts a self-supporting design (C-shaped profile or similar), with high strength and no need to install a frame.
Drawer height: 8E/4 (200mm) and 8E/2 (400mm) are the most commonly used basic units (1E=25mm), and there are also specifications such as 16E/8 (200mm) and 24E (600mm). A single cabinet can install up to 21 8E/4 units (or corresponding combinations).
Standardized compartments: Strictly divided into vertical busbar compartments, horizontal busbar compartments, cable compartments, drawer functional unit compartments, control circuit compartments, etc., and each compartment is isolated with galvanized steel plates or insulating plates, which is highly safe.
Withdrawable structure:
Functional units (circuit breakers, contactors, instruments, etc.) are installed in the drawer.
The drawer has a working position (Connected), a test position (Test), and a disconnected position (Disconnected/Withdrawn).
Working position: The main circuit and the control circuit are both connected.
Test position: The main circuit is disconnected (separated by the primary isolation contact), and the control circuit is connected. The secondary circuit (such as closing and opening, signaling, protection) can be tested safely.
Disconnected position: The drawer is completely withdrawn or in an isolated state, and the main circuit and the control circuit are disconnected, which is convenient for maintenance and replacement.
Busbar system:
Horizontal busbar: Located at the top of the cabinet or the upper rear busbar room, the rated current can reach 6300A (depending on the design), and copper busbars are generally used.
Vertical bus: Located in the vertical bus room at the rear of the cabinet, the rated current is usually 1000A (there are also higher specifications such as 1600A). The "sandwich" structure is adopted to wrap the bus in the insulating functional board, which is extremely safe and has low temperature rise.
Distribution bus: The drawer unit is connected to the vertical bus through a primary isolation contact.
Interlocking and safety:
Mechanical interlock: Ensure that the drawer can only be moved after the circuit breaker is opened (from working position -> test position -> separation position, or reverse insertion). The circuit breaker cannot be closed when the drawer does not reach the correct position (working position or test position).
Electrical interlock: More complex interlock logic (such as dual power interlock) can be provided.
Valve mechanism: After the drawer is pulled out, the insulating valve of the vertical bus room is automatically closed to prevent personnel from touching the live bus. Safety is the core highlight.
Reliable grounding system.
Secondary connector:
The control circuit connection between the drawer and the cabinet is realized through a high-reliability, guided plug-in secondary connector (usually 20 cores or more). Automatic connection/disconnection when the drawer is moved.
The secondary wire is pre-connected in the drawer to reduce the workload and error rate of on-site wiring.
Drawer type (common classification of MNS 2.0 and previous versions):
Type 1 drawer: Small current (≤63A), the operating mechanism is integrated with the circuit breaker, and the operating shaft cannot be withdrawn. The secondary wire needs to be disconnected to replace the unit.
Type 2 drawer: Medium current (≤250A), the operating shaft can be withdrawn. When replacing the functional unit, only the operating shaft needs to be withdrawn, and there is no need to disconnect the secondary wire, which is better for maintenance.
Type 3 drawer: High current (250A - 630A and above), usually semi-drawable or fixed partition. The main switch is large, the drawer body may not move, and operation and isolation are achieved by moving the operating mechanism. The Type 3 solution is extremely flexible.
Large industrial plants: Main power distribution and motor control in petrochemical, chemical, metallurgical, pharmaceutical, automobile manufacturing, etc.
Large commercial buildings and infrastructure: Power distribution centers and floor power distribution in super high-rise buildings, large shopping malls, hospitals, data centers, airports, subway stations.
Public utilities: Power supply systems of power plants, water treatment plants, waste incineration power plants.
Demanding places: Dust, humidity and other environments (benefiting from high IP protection levels).
Occasions that require extremely high power supply continuity and rapid maintenance.
