MNS Series Low Voltage Withdrawable Switchgear

Overview

MNS Series Low Voltage Withdrawable Switchgear is used as the control equipment for power distribution and asynchronous motor of three-phase AC frequency of 50 (60) Hz and rated working voltage of AC 380V (660V) system.

The switchgear is advanced type drawer type low voltage complete switchgear, it consists of one or more closed control cabinet, the control cabinet mainly consists of a number of its main circuit switching appliances and control measurement components according to the function of the functional unit circuit brought together. Functional unit according to the upper and lower stacked mounted in a closed metal cabinet, and with the cabinet of the vertical bus through the plug-in connection.

MNS Series Low Voltage Withdrawable Switchgear is widely used in power plants, metallurgy and steel rolling, petrochemical industry, light industry and textile industry, port terminals, buildings and hotels, etc. as a three-phase, four-wire or five-wire system, voltage 380V, 660V, frequency of 50Hz, rated current of 5000A and the following power supply system for the power distribution and centralized control of electric motors.

MNS is assembled with advanced type low voltage switchgear after comprehensive type test and obtaining CCC certification, and is designed in accordance with the following standards:
National standard GB7251.1 -2005 “Low-voltage complete sets of switchgear
International standard old C60439.1-1992 “Low-voltage complete sets of switchgear and control equipment”.

Working Conditions

Ambient temperature：-30℃ ~ +50℃，and measuring average RH within 24 hours ≤+50℃；
Altitude: Not exceed 2000m above sea level；
Ambient humidity: Daily average RH ≤ 95%; Monthly average RH ≤ 90%
Earthquake intensity: ≤ Degree 8
Water vapor pressure:Daily average RH ≤ 2.2kPa; Monthly average RH ≤ 1.8kPa;
Ambient environment: no fire, explosion danger, serious pollution, chemical corrosion and severe vibration place

Technical Parameters

product specification

No.	Item	Parameters
1	Rated insulation voltage	690V(1000)V
2	Rated working voltage	380V,400V,690V
3	Maximum working current of main bus	6300A
4	Rated withstand current of main busbar	100kA/1s
5	Main busbar rated peak withstand current	220kA/0.1s
6	Maximum operating current of branch distribution bus (vertical bus)	2000A
7	Peak current of distribution bus (vertical busbar):
8	Standard type	105kA(Max)/0.1s
9	Reinforced type	176kA(Max)/0.1s
10	Protection level	IP41

Internal Structure

Cabinet structure

Its basic structure is an assembly of C type profiles which made from plate bending with E=25 module installation hole. The whole cabinet and inner compartments are purification treatment of zinc plating. The door panels and side panels are electrostatic sprayed.The cabinet basic structure is as picture.1 and basic size as picture.2 (table 1 and 2)

Cabinet type

Power Distribution Center switchgear (PC): can adopt Emax,MT,3WN,AH,ME series circuit breakers.
Motor control center switchgear (GCK、GCS、MNS) : it is the assembly of big & small drawer, every circuit main switch is high breaking moulded case circuit breaker or rotation type load break switch with fuse.
Power factor automatic compensation cabinet is with manual or automatic and remote power factor compensation device.

A Power distribution center (PC) cabinet

Height	Width	Depth			Remark
H	B	T	T1	T2	Remark
2200	400	1000	800	200	Main bus transfer
2200	400	1000	800	200	Fs-1250-2000 ME630-1605
2200	600	1000	800	200	Fs-2500
2200	800	1000	800	200	Fs-3200 ME2000-3200
2200	1000	1000	800	200	Fs-4000 ME3205
2200	1200	1000	800	200	ME4005

B Power distribution center (PC) cabinet

Height	Width			Depth			Remark
H	B	B1	B2	T	T2	T2	Remark
2200	1000	600	400	600	400	200	Single-side operation
2200	1000	600	400	1000	400	200	Double-side operation

C type composed frame structure (Figure 1)

Schematic diagram of cabinet (Fig 2)

Cabinet compartment design

Power distribution center (PC).

In the PC cabinet ,there has 3 compartments.
The horizontal busbar compartment is at the back of the cabinet.
Function unit compartment is at the front of cabinet or the left of cabinet.
The way of compartment: use steel plate between the horizontal busbar compartment and function unit compartment. Use flame retardant polyphenylene oxide plastic shell between the circuit controlling compartment and function unit compartment.
Inner installed air circuit breaker ,which can be operated by manual at outside cabinet when the door is closed. To determine whether the circuit breaker is in the test position or in the service position by observing circuit breaker ON-OFF state and the position between door and controlling systems.
Between the main circuit and auxiliary circuit ,designing the compartments structure to auxiliary electric units like instrument, signal lamps & push buttons etc ,which are fixed on the plastic plate . At the back of this plate, the shell made of flame retardant polyamine foam plastics ,which is separated from the main circuit.

Withdrawable type motor control center & small current power distribution center (GCK、GCS、MNS):

Withdrawable GCK、GCS、MNS cabinet ,there also has 3 compartments, that is horizontal busbar compartment at the back of the cabinet, function unit compartment at the front left of the cabinet, cable compartment at the right of the cabinet. Separation of functional panel made of flame retardant foamed plastics between the horizontal busbar compartment and functional units compartment. Separation of steel panel between cable compartment, horizontal busbar compartment and functional unit compartment.

The GCK、GCS、MNS drawer has below 5 types:

The rear structure of outgoing :

This back outlet is designed for decreasing the arrangement width of the switchgear. Its main busbar is installed horizontally on the top of the cabinet, on the half of back is cable compartment. The incoming cables are all connected in this cable compartment. The front of the switchgear is a device small chamber to install functional units or parts. This system design will move the cable compartment at the side of the panel back ,which hardly decrease the arrangement width of cabinets to further satisfy the space requirements of power substation.
The width of feeder panel is 600mm,depth 1000/1200 mm. On its top, it is independent of the main bus compartment separated from device small chamber. The height of front device chamber is 72E(E=25mm) which separated from the back cable compartment through the multi-functional panel, fully usage of installation space of the cabinet. Its structure is compact & flexible unit configuration. The back cable compartment is with the door for convenient installation & maintenance . The width of incoming is according to the frame-current of incoming units . Advised width is 400/600/800/1000mm,cabinet depth 1000mm.

MNS Series Low Voltage Withdrawable Switchgear

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