NKU MK is a low-voltage complete device for one-way (two-way) service in air-insulated metal cases, with stationary and/or withdrawable circuit breakers, stationary load switches with fuses, current transformers, control and signaling devices. Designed for distribution of three-phase alternating current electricity with a voltage of 380/220 V and a frequency of 50 Hz in networks with a grounding system TN-C, TN-CS, TN-S, for protection against overloads and short circuits, as well as for control, measurement and signaling.
The design of the MK NKU has a modular construction principle, which makes it possible to manufacture switchboards of any configuration with various options for separating functional units. The cable and busbars can be supplied at the top or bottom of the switchboard. A wide range of circuit solutions provides freedom of choice of technical solutions for each specific object (customer). The use of load switches with fuses, circuit breakers with microprocessor units, control and signaling devices allows the implementation of low-voltage switchgear with distribution circuits of varying levels of complexity.
The devices are installed in stationary or retractable modules, all controls are located on the front side. Operation control and management are carried out without opening the doors.
Advantages
Variety of design and circuit solutions
High reliability of the frame and bus system Full factory readiness
Possibility of two-way service Retractable blocks
Protection degree up to IP65
Easy and safe maintenance Small dimensions
Modular design principle Remote control and data collection
Rated impulse withstand voltage of the main circuit, kV
4, 6, 8, 12
Rated insulation voltage of main circuits, V
660
Design
• Cabinet-made NKU is a metal structure assembled in a frame made of sheet metal (galvanized steel) 2-2.5 mm thick, or a welded frame made of sheet metal 2-2.5 mm thick, removable panels and doors 1-2 mm thick, powder coated RAL7035. Metal structure parts are made using high-precision equipment using cold stamping
• NKU consists of one or more independently transportable sections (hereinafter sections)
• Conducting busbars are located in compartments. They consist of main (prefabricated), group (distribution) three-phase busbars, a zero operating busbar and a zero protective conductor located in the lower or upper part of each cabinet. Horizontal busbars are installed on insulators (busbar holders). Vertical distribution busbars are connected to them. The main busbars are located at the bottom, middle or top of the cabinet. Group buses are located behind or to the left or to the right of the section with the switching device
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Each cabinet is equipped with a protective zero bus PE (or PEN bus) for grounding the equipment shell and it is possible to connect the protective zero conductor of the cable of each connection (input, output) to the protective bus. To make such connections, the busbar design provides a number of holes
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The front panels of the NKU are doors, closures or panels of pull-out units. The side walls of the NKU are removable panels. Metal partitions between cabinets can be made from a whole sheet or from individual elements
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All doors of the switchgear are equipped with locks that can be unlocked and locked using a key
To ensure the safety of operating personnel and depending on the form of sectioning in accordance with GOST 51321.1, NKU cabinets are divided into compartments due to internal partitions: busbar compartment, incl.
distribution busbars, functional blocks, cable connection compartment (clamps for external conductors)
All built-in switching devices and withdrawable units are equipped with mechanical and electrical interlocks. The rolling out mechanism is equipped with a lock that prevents movement under load, as well as a stop that limits its maximum movement.
