Product Introduction
MNS low-voltage draw-out switchgear (hereinafter referred to as switchgear) is developed by our company after referring to the MNS series low-voltage switchgear of foreign companies and making comprehensive improvements. It is currently an excellent low-voltage draw-out switchgear in China. This product is composed of standardized and series modules, and the drawer has reliable mechanical interlocking device, which makes users safer and more reliable when using.
This switch cabinet is applicable to the three-phase five-wire power supply system with AC 50 (60) Hz, rated working voltage 400V, 660V and rated current 5000A and below. It can be used in power plants, substations, industrial and mining enterprises, buildings, hotels, airports, docks, radio and television and other communication centers to control power generation, power transmission and distribution, power conversion and power consumption equipment, and reactive compensation for its main bus through the capacitance compensation cabinet. Compliance standard: GB7251.1 Low-voltage Switchgear and Low-voltage Switchgear and Control Equipment (IEC60439)
Working conditions
◆ The ambient air temperature shall not be higher than+40 ℃, not lower than - 5 ℃, and the average temperature within 24h shall not be higher than+35 ℃.
◆ The relative humidity of the surrounding air is not more than 50% at a higher temperature of+40 ℃, and there is a higher relative humidity at a lower temperature, such as 90% at+20 ℃. However, due to the change of temperature, there may be occasional moderate condensation.
◆ For indoor use, the altitude of the place of use shall not exceed 2000m.
◆ It should be installed in a place without severe vibration and impact, and without corrosion of electrical components.
structure characteristics
Due to the introduction of excellent technology and technical improvement on its original basis, this switchgear is more in line with China's national conditions. The cabinet body is made of 25 mm modular C profiles through connectors to form various cabinet frame structures and drawer units that can meet various requirements. The high-strength flame-retardant engineering plastic components are used in the MCC cabinet to make its safety performance more reliable. At the same time, the foreign functional boards are modified and combined with 200 mm modular, which is more conducive to the design requirements of the mixed cabinet body of PC cabinet and MCC cabinet, The extraction unit and the cabinet body have reliable interlocking devices to prevent the switch from being pulled with load when the switch is powered on, which improves its safety. In addition, the cabinet body is generally assembled by cold-rolled steel plate after passivation treatment, and aluminum coated zinc steel plate can also be used according to the different needs of users.
◆ Switch cabinet type
◇ Power receiving and bus coupler cabinet
Various types of frame circuit breakers at home and abroad, such as RMW1, CW1, NA1, DW45, CDW7, MT, E and other series circuit breakers, are used as the main switch to realize the power receiving or bus coupling functions.
◇ Power center cabinet (PC)
Various types of cabinet type circuit breakers at home and abroad, such as DW45, NA1, CDW7MT and E series circuit breakers, are used for power distribution.
◇ Motor control center (MCC)
It is assembled by large and small drawers, and the main switch of each circuit adopts molded case circuit breaker with high breaking capacity or rotary load switch with fuse.
◇ Reactive power compensation cabinet
◆ Drawer type
Five sizes are designed with modular structure at the height of 8E (200mm). The effective component installation height is 1800mm, which makes the overall layout of the cabinet more reasonable and beautiful.
8E/4: 200 high × Width 150 × Four drawer units with a depth of 400 height are combined in parallel
8E/2: 200 high × Width 300 × Two drawer units with a depth of 400 height are combined in parallel
8E: 200 high × Width 600 × One drawer unit is assembled in the space with a depth of 400
16E: 400 high × Width 600 × One drawer unit is assembled in the space with a depth of 400
24E: 600 high × Width 600 × 400 deep, assemble 1 in 24E (600mm) high space
Drawer unit
◆ Cabinet introduction
◇ Basic dimensions of cabinet
◇ Cabinet partition design
MNS cabinet can form single-sided operation cabinet or double-sided operation cabinet as required, and each cabinet body is fixed and divided into three compartments. Namely, main bus room, electrical room and cable room. (See Figure 2 for details)
◇ Safety protection system
Each cabinet is equipped with a flame-retardant high-density polyurethane plastic functional board, or an electroplated partition board installed between the main bus room and the electrical room. Its function is to effectively prevent the accidents caused by flashover and short circuit between the bus caused by the fault of the switch elements, and make the operation safer. The upper and lower drawers are separated by galvanized metal base plates with ventilation holes, which has strong isolation effect between adjacent circuits. A variety of plastic components are used in the cabinet to support the live parts. These components are required to be halogen-free and have CTI300 anti-leakage performance. The cabinet is equipped with an independent PE grounding system and N neutral conductor, which run through the whole device. Each circuit can be connected to the ground or neutral nearby. The installation of the whole bus system is shown in Figure 3. The frame structure is connected with self-tapping screws, which has high grounding reliability. (See Figure 3 for details)
◆ Bus system
The horizontal bus of the switch cabinet is arranged in the horizontal bus isolation room of the switch cabinet, which can be placed behind the cabinet or on the top of the cabinet. The horizontal bus in the cabinet body of the rear outlet structure is placed on the top of the cabinet. The distribution bus (vertical bus) is assembled in the flame-retardant plastic functional plate, which can prevent the discharge caused by electric arc and human contact, and is connected with the main bus through the connector.
◆ Electrical and mechanical interlocking of drawer
The drawer unit is equipped with reliable mechanical interlocking device, which is controlled by the operating handle and has obvious opening, closing, test, extraction and isolation positions. In order to strengthen the safety precautions, padlocks can be added after the operating handle is positioned, and at most three locks can be added.
◆ Rear outgoing switch cabinet structure
The outgoing line behind the cabinet can reduce the arrangement width of the switch cabinet. The main bus of the rear outgoing switch cabinet is horizontally installed on the top of the switch cabinet, the rear half of the cabinet is a cable room, and the incoming and outgoing cables are connected in the cable room behind the cabinet. The front of the switchgear is the device compartment, which is installed with the functional units of the switchgear. The system design moves the cable room on the side of the switch cabinet to the rear half cabinet, greatly reducing the arrangement width of the switch cabinet, so as to further meet the requirements of the spatial layout of the substation.
The feeder cabinet is 600mm wide and 1000mm deep, and the top is an independent bus compartment, which is isolated from the device compartment. The effective installation height of the front device compartment is 72E (E=25mm). It is isolated from the rear cable compartment through the multi-function board, making full use of the installation space of the switch cabinet, with compact structure and flexible unit configuration. The rear cable room is equipped with a door, which is convenient for installation and maintenance. See Figure 4 for appearance.
The width of the incoming cabinet is determined according to the frame current of the incoming unit. The recommended width is 400, 600, 800 and 1000mm, and the cabinet depth is 1000mm.
Selection of circuit components
The components in the device are mainly electrical components with perfect technical performance indicators or with imported technology that can be produced in batches in China.
A. DW45 series, NA1 series and AE series are selected for power incoming line and feeder circuit of main circuit breaker 630A and above Train, CW or RMW series, MT series, E series or IZM series can also be selected.
B. Circuit breakers for feeder and motor control below 630A are mainly CDM1 series, CM1 series, TM30 series, NM1 series, RMM1 series, NS series, S series, NZM series molded case circuit breakers, etc.
C. The AC contactor mainly adopts the CDC7, LC1, 3TB and CJX2 series contactors, as well as the matching thermal relay and interlocking mechanism.
D. Current transformers shall be BH series, SDH series, LMK series, etc.
E. The fuse shall be RT series or NB series with high breaking capacity.
Installation and use
After the product arrives at the receiving place, it is necessary to check whether the package is intact. If any problem is found, it is necessary to notify the relevant departments of the contract in time to make business records, analyze the causes together, and make visa and aftermath treatment.
For products that are not installed immediately, they should be placed in a proper place and properly stored according to normal use conditions and temporary storage regulations for electrical equipment.
◆ The installation of the product should follow the installation diagram 5. The foundation channel steel and the bolts used for bolt fixation shall be prepared by the user. When the main bus is connected, if the surface is uneven due to transportation, storage and other reasons, it should be leveled before connecting and fastening.
◆ When the equipment is installed separately or in rows, its perpendicularity and the deviation of the cabinet surface unevenness and the gap between cabinets shall comply with the provisions in Table 1.
◆ Inspection and test after installation and before putting into operation.
◇ Check whether the cabinet surface paint or other covering materials (such as plastic spraying) are damaged, whether the cabinet is dry and clean, and whether the installation screws of each part are loose.
◇ Whether the operating mechanism of electrical components is flexible and free from jamming or excessive operating force.
◇ Whether the main electrical appliances are reliable and accurate.
◇ The drawer or draw-out mechanism shall be flexible, portable and free from jamming and collision.
◇ The center line of the dynamic and static contacts of the drawer or draw-out structure should be consistent, and the contact should be tight. The insertion depth of main and auxiliary contacts shall meet the requirements. The mechanical interlocking or electrical interlocking device shall act correctly, and the locking or unlocking shall be reliable.
◇ Drawers with the same primary scheme, secondary principle and drawer size shall be easily interchangeable without jamming and collision.
◇ When replacing the fuse core of the fuse, it should meet the requirements of the engineering design.
◇ The setting value of protection shall be set correctly according to the actual load.
◇ The insulation resistance measured with a 1000V megger shall not be less than 10M Ω.
◇ The connection of each bus shall be good, and the insulation support, installation parts and other accessories shall be installed firmly and reliably.
◆ Precautions for use
◇ The equipment is a low-voltage distribution cabinet that is not installed against the wall, operated in front and maintained on both sides. Only qualified personnel can enter or open the maintenance access and door of the cabinet for operation, inspection and maintenance.
◇ After connecting the cables, the bottom of the switch cabinet should be closed to prevent small animals from climbing into the cabinet and causing short circuit accidents.
◇ The air circuit breaker and molded case circuit breaker will be partially burned and produce carbon substances after many times of opening and closing, especially after short circuit opening and closing, which will increase the contact resistance. Maintenance and repair should be carried out according to the circuit breaker operating instructions.
◇ After installation and maintenance, the isolation between compartments and functional units must be strictly checked to ensure the good functional separation of the device and prevent the expansion of fault.
◆ Operation of drawer
◇ Operation of 8E/2 drawer and 8E/4 drawer
The 8E/2 drawer and 8E/4 drawer of MNS cabinet are equipped with special operating mechanism. The opening, closing, testing, isolation and locking functions of the switch are realized through the operating handle installed on the drawer panel within 360 ° rotation range. The operating mechanism is also equipped with a microswitch for electrical locking.
Outline and installation dimensions
See Table 2 for external dimensions
The installation of MNS series switch cabinet is not vertical to the wall, and its rear is the outlet cable trench of the cabinet. For the convenience of maintenance, the distance from the rear to the wall is usually 800~1200mm, and the front distance installation is shown in Figure 5.
Factory data and accessories
The manufacturer shall provide the following documents and accessories when supplying
Shipping list
Product certificate and delivery test report
an instruction manual
Relevant electrical drawings
Description of main components
Cabinet door key, operating handle and spare parts specified in the contract.
Ordering instructions
When ordering, the user shall provide:
Main circuit distribution system diagram and layout plan, rated working voltage, rated working current, protective device setting current and necessary technical parameters.
Indicate the specifications of incoming and outgoing cables.
Model, specification and quantity of main electrical components in the switch cabinet.
If the bus bridge or bus duct is required between the switch cabinets or the incoming cabinet, the specific requirements such as span, height from the ground, etc. shall be indicated.
When the switch cabinet is used under special environmental conditions, it shall be specified when ordering.
Surface color of switch cabinet and other specific requirements.
