Overview

MNS type low-voltage tap-type switchgear (hereinafter referred to as switchgear) was developed by our company after referring to the MNS series of low-voltage switchgear of swiss ABB company and comprehensive modification. The product is composed of standardized and series modules, and the drawer has reliable mechanical interlocking device, which makes the user safer and more reliable in use.

This switch cabinet is suitable for AC 50(60) Hz、 rated working voltage 400 V、660V. rated current 5000 A and below three-phase five-wire power supply system, can be used in power plants, substations, industrial and mining enterprises, building hotels, airports, wharves and radio and television communication centers, as power generation, transmission and distribution, power conversion and power consumption equipment control, and through the capacitor compensation cabinet to its main bus reactive power compensation. National Standard: GB7251.1《 Low Voltage Switchgear IEC60439《 Low Voltage Switchgear and Control Equipment

Model meaning

Normal operating conditions

♦ Ambient air temperature is not higher than +40℃, not lower than -5℃, and its average temperature is not higher than +35℃ within 24h.
♦ The relative humidity of the surrounding air does not exceed 50% when the maximum temperature is +40℃, and has a higher relative humidity at lower temperatures, such as 90% at +20℃, but it may be accidental due to temperature changes Produces moderate condensation.
♦ For indoor use, the altitude of the place of use must not exceed 2000m.
♦ It should be installed in a place where there is no severe vibration and impact, and no corrosion of electrical components is used.

Main parameters

Structural characteristics

This switchgear has introduced advanced technology from Swiss ABB and improved the technology on its original basis to make it more in line with my country’s national conditions. The cabinet body adopts 25mm C-shaped material through connecting pieces to form a variety of cabinet frame structures and drawer units to meet various needs. High-strength flame-retardant engineering plastic components are used in the MCC cabinet to improve its safety performance. Reliable, at the same time, the foreign function board is modified and combined with 200mm as the modulus, which is more conducive to the design requirements of the PC cabinet and MCC cabinet mixed cabinet body, and the extraction unit and cabinet body have a reliable interlock , In order to prevent the switch from being loaded with a load when the switch is energized, which improves its safety. In addition, the cabinet is generally assembled by passivation treatment of cold-rolled steel plates, and aluminum-zinc coated steel plates can also be used according to different needs of users. .
♦ Switch cabinet type
◇Received power and mother 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 function.
◇Power Center Cabinet (PC)
Various types of cabinet 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)
Assembled by large and small drawers, each circuit main switch uses a high-breaking capacity plastic case circuit breaker or a rotary load switch with a fuse.
◇Reactive power compensation cabinet
♦ Drawer type
The five sizes are all designed with a modular structure of 8E (200mm) height, and the effective component installation height is 1800mm, which makes the overall layout of the cabinet more reasonable and beautiful.
8E/4: Height 200× Width 150× Depth 400 Height Space parallel combination 4 drawer units
8E/2: Height 200× Width 300× Depth 400 Height Space parallel combination 2 drawer units
8E: Height 200× Width 600× Depth 400 Height Space Assembly 1 drawer unit
16E: Height 400× Width 600× Depth 400 Height Space Assembly 1 drawer unit
24E: Height 600× Width 600× Depth 400 Assemble one at 24E (600mm) height space
Drawer unit
The above five drawer units can be assembled in a single cabinet or mixed assembly (see Figure 1)

♦ Introduction
◇ Basic dimensions of cabinet
Power receiving cabinet and contact cabinet

Power Centre (PC) Cabinet

Electric motor control center (MCC) cabinet and capacitor compensation cabinet

◇ Cabinet partition design
The MNS cabinet can be composed of a single-sided operation cabinet or a double-sided operation cabinet according to needs, and each cabinet body is fixedly divided into three small rooms. Namely the main busbar room, electrical appliance room and cable room. (See Figure 2 for details)
◇ Security protection system
Each cabinet has a flame-retardant high-density polyurethane plastic function board, or a plated partition is installed between the main busbar room and the electrical room.
The accident caused by the short circuit between the arc and the busbar makes the operation safer.
There is a galvanized metal bottom plate with ventilation holes between the upper and lower drawers to isolate, which has a 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 level leakage resistance.
The cabinet is equipped with an independent PE grounding system and N-neutral conductors, which run through the entire device, and each loop can be connected to the ground or zero. The installation of the entire busbar system is shown in Figure 3. Frame structural parts are connected by self-tapping screws, which have high grounding reliability. (See Figure 3 for details)
♦ Busbar system
The horizontal bus bar of the switch cabinet is arranged in the horizontal bus bar isolation room of the switch cabinet, and can be placed behind the cabinet or on the top of the cabinet. Distribution bus (vertical bus) group
Installed in the flame-retardant plastic functional board, it can not only prevent the discharge caused by the arc, but also prevent the human body from contacting, and connect with the main bus bar through the connecting piece.
♦ Electrical and mechanical interlocking of drawers
The drawer unit has a reliable mechanical interlocking device, which is controlled by the operating handle, and has obvious opening, closing, testing, drawing and isolation positions. To strengthen safety precautions, padlocks can be added after the operation handle is positioned, and up to three locks can be added.
♦ Rear outlet switch cabinet structure
The outlet line behind the cabinet can reduce the arrangement width of the switch cabinet. The main busbar of the rear outlet switch cabinet is installed horizontally on the top of the switch cabinet. The rear half of the cabinet is the cable compartment, and the incoming and outgoing cable are connected in the cable compartment behind the cabinet. The front of the switchgear is the device compartment, and the functional unit of the switchgear is installed. The system design moves the cable room on the side of the switch cabinet to the second half of the cabinet, which greatly reduces the arrangement width of the switch cabinet to further meet the requirements of the substation space layout.
The feeder cabinet is 600mm wide and 1000mm deep. The top is an independent busbar room, which is isolated from the device compartment. The effective installation height of the front device compartment is 72E (E=25mm), which is isolated from the rear cable compartment by the multi-function board, making full use of the installation space of the switch cabinet, compact structure and flexible unit configuration. The rear cable compartment is provided with a door, which is convenient for installation and maintenance.
See Figure 4 for appearance.
The width of the incoming cabinet is determined by the frame current of the incoming unit. The recommended width is 400, 600, 800, 1000mm, and the cabinet depth is 1000mm.

Circuit Components Selection

The components in the device mainly use electrical components with advanced technical performance indicators or imported technology that can be mass produced in China.
a. Main circuit breaker 630A and above power supply line and feeder circuit, the main selection is DW45 series, NA1 series, AE. series, CW or RMW series, can also use imported MT series, E series or IZM series.
b. The circuit breakers for feeder and motor control below 630A are mainly selected from CDM1 series, CM1 series, TM30 series, NM1 series, RMM1 series, and imported NS series, S series, NZM series molded case circuit breakers, etc. can also be selected.
c. The AC contactors mainly use CDC7, LC1 series, 3TB series, CJX2 series contactors, as well as the matching thermal relay and interlocking mechanism.
d. Current transformers use BH series, SDH series, LMK series, etc.
e. The fuse selects RT series or NB series with high breaking capacity.

 Installation and Use

After the product arrives at the place of receipt, first of all, it should be checked whether the packaging is intact, and if any problem is found, the relevant department of the contract should be notified in a timely manner to make business records, analyze the reasons together, and complete the visa and aftercare.
For products that are not installed immediately, they should be placed in an appropriate place and properly stored according to the normal use conditions and the requirements for temporary storage of electrical equipment.
♦ The installation of the product should be carried out according to the installation diagram 5. The base channel steel and the bolts when bolting is used are prepared by the user. When the main busbar is connected, if the surface is uneven due to transportation, storage, etc., it needs to be smoothed before connecting and tightening.
♦ When the equipment is installed alone or in a row, the verticality, the unevenness of the cabinet surface and the deviation of the gap between the cabinets should meet the requirements of Table 1.
♦ Inspection and test before product put into operation after product installation.
◇Check whether the cabinet finish paint or other covering materials (such as spray plastic) are damaged, whether the cabinet is dry and clean, and whether the mounting screws of each part are loose.
◇Whether the operating mechanism of electrical components is flexible, and there should be no stagnation or excessive operating force.
◇ Whether the on and off of the main electrical appliances are reliable and accurate.
◇Drawer or draw-out mechanism should be flexible, light, free of jamming and collision.
◇The center line of the dynamic and static contacts of the drawer or withdrawable structure should be consistent, and the contact should be tight. The insertion depth of the main and auxiliary contacts should meet the requirements. The mechanical interlocking or electrical interlocking device shall act correctly, and the locking or releasing shall be reliable.
◇The drawer with the same plan, second principle and same drawer size should be easily interchangeable without jamming or collision.
◇When replacing the fuse core, it should meet the requirements of engineering design.
◇The setting value of protection should be set correctly according to the actual load.
◇Measure the insulation resistance value with a 1000V megohmmeter not less than 10MΩ.
◇The connection of each bus bar should be good, and the installation of insulating supports, mounting parts and other accessories should be firm and reliable.
♦ Precautions for use
◇The equipment is a low-voltage distribution cabinet that is not installed against the wall, is operated on the front, and is maintained on both sides. The maintenance channel and door of the cabinet must only be accessed or opened by qualified professionals for operation, inspection and maintenance.
◇After connecting the cable, the bottom of the switch cabinet should be closed to prevent small animals from climbing into the cabinet and causing a short circuit accident.
◇After multiple opening and closing of air circuit breakers and molded case circuit breakers, especially after short circuit opening and closing, the contacts will be burned and carbon materials will be generated, which will increase the contact resistance.
The maintenance and repair should be carried out according to the instruction manual of the circuit breaker.
◇After installation and maintenance, the isolation between the compartments and functional units must be strictly checked to ensure the good functional separation of the device and prevent the expansion of failures.
♦ Drawer operation
◇ Operation of 8E/2 drawer and 8E/4 drawer
The 8E/2 drawer and 8E/4 drawer of the MNS cabinet are equipped with a special operating mechanism. The operation handle installed on the drawer panel can realize the functions of opening, closing, testing, isolation and locking of the switch within a 360° rotation range. The operating mechanism is also equipped with a micro switch, which is used for electrical blocking.

Working position: the main switch is closed, the main circuit and the control circuit are connected, and the functional unit is locked.

Opening position: the main switch is open, the control circuit is connected, and the functional unit is locked.

Test position: The main switch is opened, the main circuit is disconnected, the control circuit is connected, and the functional unit is locked.

Pumping position: Both the main circuit and the control circuit are disconnected. The drawer can be pulled or pushed.

Isolation position: drawer draws 30mm. The main and control circuits are isolated and disconnected, and the drawer is locked.

After the operating handle is pushed inward, it can be turned from the “open position” to the “working position“.
The operating handle can be padlocked at the three positions of main switch opening, testing and isolation. As a safety guarantee, up to 3 locks can be added.
Working process: In the “drawing position“, the drawer can be pushed and pulled out. After the drawer is pushed, the operating handle is rotated counterclockwise by 45° to draw the drawer 30mm to the “isolated position“. After pushing the drawer in the “extraction position“, the operating handle rotates clockwise 45° to the “test position“, and then rotates 45° clockwise to the “opening position” of the main switch. After turning 90°, the switch is closed, if you need to exit, then reverse the operation in turn.

b. Operation of 8E, 16E, 24E drawers
The drawer panel of MNS cabinet 8E and above is equipped with a mechanism operation handle and a switch operation handle. Through the cooperation of the mechanism operation handle and the switch operation handle, the functions of opening, closing, testing, isolation and locking are realized. Or molded case circuit breaker), the operating handle of the mechanism realizes the position of the drawer, such as the test position, the extraction position, the isolation position, and the working position.

Mechanism operating handle position:

Working position: the mechanism is locked, the main switch (isolating switch and molded case circuit breaker) can be operated (through the switch operating handle), and the main operating switch can be turned to the test position after the main switch is opened.

Test position: the main switch is opened, the control circuit is connected, and the functional unit is locked.

Withdrawal position: the main switch is opened, the main circuit and the control circuit are disconnected, and the drawer can be pulled or pushed in.

Isolation position: The component is drawn out 30mm, the main circuit and the secondary circuit are disconnected, and the mechanism is mechanically interlocked and locked.

O    Switch operating handle position:

Main switch open position;
Main switch closed position.
Note: The switch operating handle can only be operated when the mechanism operating handle is in the working position. The mechanism can only operate the switch handle when the main switch is mechanically locked.
Working process: When the switch operating handle is in the ” O ” position, the mechanism operating handle is in the withdrawn position, the drawer can be pulled out and advanced. After the drawer is advanced, the mechanism operating handle is turned counterclockwise after 45°, the drawer is drawn 30mm, reaching the “isolation” Location“. In the “pulling position“, after pushing the drawer, turn the operating handle of the mechanism clockwise 45° to reach the “test position“, and then rotate clockwise 45° to reach the “working position“, then turn the switch operating handle clockwise 90°, the main The switch is closed. If you need to exit, do the reverse operation in turn.
♦Unlock device
There is a small plastic cover in the lower right corner of the drawer panel of 8E and above, this is the door unlocking mechanism: When the drawer is in the “working position“, if you want to open the door, first open the switch, then pull out the small cover, and then use Insert a small screwdriver into the hole and move the lock downward to open the door. After closing the door, be sure to cover the small plastic cover, otherwise it will destroy the original protection level.

 Shape and mounting dimensions

The installation MNS series switchgear is a vertical installation of the non-client wall, and its rear is the outlet cable trench of the cabinet body. For easy maintenance, the rear distance from the wall is usually 800-1200 mm, and the front distance installation is shown in figure 5.

Factory Information and Accessories

The manufacturer should provide the following documents and accessories when supplying
Shipping list
Product certificate and factory test report
user’s Guide
Related electrical drawings
Main component specification
Cabinet key, operation handle and spare parts specified in the contract.

Order Notes

When ordering, the user should provide:
Main circuit distribution system diagram and plane layout diagram, rated working voltage, rated working current, protection device
Set current and necessary technical parameters.
Indicate the cable specifications of the incoming and outgoing lines.
The model, specification and quantity of the main electrical components in the switch cabinet.
If a bus bridge or bus duct is required between switch cabinets or incoming cabinets, the specific requirements such as span and height from the ground shall be indicated.
When the switchgear is used in special environmental conditions, it should be explained in detail when ordering.
Switchgear surface color and other specific requirements.