1. Purpose
MNS Low-voltage withdrawable switchgear suitable for three-phase four-wire and three-phase five-wire power system with AC 50-60 Hz, rated voltage of 660V, below the rated current 4000A as the receiving and distributing electric energy, is widely used in power distribution center (PC) and motor control center (MCC) of power plants, substations, industrial enterprises and high-rise buildings.
This product meets the standards of GB7251, ZBK36001 and IEC439-1 (1992).
2. Service conditions
(1. Ambient air temperature does not exceed +40 ° C, nor lower than -5 ° C, and the average temperature within 24 hours is not higher than +35 ° C.
（2. The relative humidity of the ambient air at the maximum temperature of 40 ° C is not more than 50%, a greater relative humidity at a lower temperature is allowed, such as90% at +20 ° C, but the condensation on the product surface due to temperature changes should be taken into account.
（3. Indoor use, the altitude of installation place shall not exceed 2000m.
(4. The device should be installed in areas without severe vibration or impact and its electrical components are free from corrosion; users with special requirements can consult with the manufacturer for solution.
3. Structural characteristics
The basic framework of the switchgear assembly adopts modular structure, the KB shape steels are tightly connected into basic framework with thread forming screws, and then doors, sealing plates, separator, mounting bracket, bus and functional units and other parts are assembled into a complete switch cabinet according to the scheme, the inside structure has been galvanized, aluminized zinc plate can also be used for modular installation (1E = 25mm). The switchgear panel is made of high-quality steel plate after CNC machining, with its surface being electrostatic sprayed after acid pickling and phosphating, wear resistant and anticorrosive, marked by strong mechanical strength and reliable grounding continuity.
Switchgear compartment can be divided into functional unit compartment, busbar compartment, and cable compartment, the function of each unit is relatively independent and separated by metal plate or flame-retardant wall between functional areas to ensure safety and to prevent accidents spreading.
Horizontal bus is flat-mounted, effectively reducing the electrical and thermal stresses. Busbar cross-section specifications include five types: 2 (30X10), 2 (60X10), 2 (80X10), 2 (100X10), 4 (60X10), corresponding to the bus current of 1250A2000A, 2500A, 3200A, 4000A, neutral grounding bus N, PE is 60X10, drawer vertical bus is 50X30X5 angle square copper bus, all buses are tin plated. MCC cabinet drawer has five specifications: 8E/4, 8 E/2, 8 E, 16E, 24E (1E = 25mm). The drawer has five positions on it: connection position, test position, breaking position, move and disengaged positions. Mechanical interlock device is set between drawers and switches, when the switch is breaking, the drawer can be drawn out or inserted; when the switch is in the closed position, the drawer can not be withdrawn or inserted. The operating mechanism can lock the switch at the breaking position with a padlock to prevent unauthorized operation, functional unit drawers of the same specification can be interchangeable. Each functional unit drawer has 16 to 32-pair corresponding auxiliary contacts to meet the needs of remote operation control, power metering and computer interfaced automatic monitoring system
4. Technical parameters
Basic electrical parameters
Rated operating voltage : AC380V，AC660V
Rated insulation voltage : AC660V，AC1000V
Rated current of horizontal bus : 1250A，2000A，2500A，3200A，4000A
Rated current of vertical bus : 1000A
Maximum current of feeder circuit : 2500A
Maximum current of drawer circuit : 630A
The maximum capacity of control motor : 320KW
Rated frequency : 50、60Hz
Peak withstand current of horizontal bus（0.1S）:105KA，176KA Short-time withstand current of horizontal bus （1S）:50KA，80KA
Peak withstand current of vertical bus （0.1S）:105KA
Short-time withstand current of vertical bus（1S）:50KA
Rated power frequency withstand voltage（1min） : 2500V
Secondary power frequency withstand voltage（1min） : 2500V
Protection level provided by enclosure : IP30，IP40
Dimensions: 600、800、1000mm Width Depth: 800、1000mm Height : 2200mm