MCC Series Of Low Voltage Withdrawable Motor Switchgear

MCC series of low voltage withdrawable motor switchgear is a kind of combination type motor panel,its technology reaches  international levels. It is suitable for control motor starting ,transformer station, electric power plant, petrochemical industry, metallurgical steel rolling ,traffic energy,light and textile industry ,and residence community, high building ..etc. As electric power energy conversation ,distribution & controlling for power distribution equipments of AC 50/60Hz rated service voltage 690V or less .It complies with IEC60439 standard 《Low Voltage withdrawable switchgear》.

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

Basic technical parameters
1.Electric performance

Rated insulation voltage	690V(1000)V
Rated working voltage	380V、400V、690V
Maximum working current of main bus	6300A
Rated withstand current of main busbar	100kA/1s
Main busbar rated peak withstand current	220kA/0.1s
Maximum operating current of branch distribution bus (vertical bus)	2000A
Peak current of distribution bus (vertical busbar):
Standard type	105kA(Max)/0.1s
Reinforced type	176kA(Max)/0.1s
Protection level	IP41

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
1.Power Distribution Center switchgear (PC): can adopt Emax,MT,3WN,AH,ME series circuit breakers.
2.Motor control center switchgear (MCC) : 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
2200	400	1000	800	200	Main bus transfer
2200	400	1000	800	200	F s-1250-2000 ME630-1605
2200	600	1000	800	200	F s-2500
2200	800	1000	800	200	F s-3200 ME2000-3200
2200	1000	1000	800	200	F s-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
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
1)Power distribution center (PC).
(1)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.
(2)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.
(3)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.
(4)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.

2)Withdrawable type motor control center & small current power distribution center (MCC):
Withdrawable MCC 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 MCC drawer has below 5 types:

8E/4: 200(H) x 150(W) x 400(D) mm	8E/2: 200(H) x 300(W) x 400(D)mm
8E :200(H) x 600(W) x 400(D) mm	16E: 400(H) x 600(W) x 400(D) mm
24E: 600(H) x 600(W) x 400(D) mm

3)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.

Busbar system
It can be equipped with 2 groups busbar which installed at the back busbar compartment of the switchgear. They are installed upper and lower back of cabinet. According to the needs of the incoming , up and down two sets of busbar can be adopted the materials with same or different cross-section. They can supply power separately ,also can supply power in parallel connection or as backup power source.

insulators, N line & PE line should be used separately . If short connection by conductor between them, it will be PE/N line.

Protect grounding system
The protection circuit is made from electrically conductive structural devices & PE lines( or PE/N lines) that are individually mounted and run through the entire length of the array . For the metal structural devices or parts, except the exterior door and seal plates, others are treated by zinc-coated.At the place of structural parts connection , do the carefully design to pass a certain short-circuit current.

Auxiliary circuit and cable tray
The auxiliary circuit cable tray is installed at the top of the compartment of the functional unit, and the connection line and the common power line can be put in the tray.

Cable and control wire connection
At the side of withdrawable parts ,in the cable small chamber installed cable connection devices and terminals for connecting outlet cable and controlling line and devices. The wiring device is arranged in the chamber on the right side of the rail cable; Main circuit terminal is at the back; Control terminal is at the front 45°direction.Use screws to connect wires for control terminal or use copper lugs or plug-in type cable lugs. The main circuit terminal of the transfer parts is less than 63A , also with PE terminal blocks.

Drawer type
There has 5 standard sizes based on height of 8E (200mm)
8E/2: assembly 2PCS drawer type units in 8E space.
8E/4: assembly  4PCS drawer type units in 8E space.
8E: assembly 1PC drawer type unit in 8E space
16E: assemble 1PC drawer type unit in 16E (400mm) space
24E: assembly 1PC drawer type unit in 24E (600mm) space
5 types of drawer unit can be assembled in a single cabinet ,can be mixed assembled too.
If assembled in a single cabinet, the max drawer No. is as parameter 3.

Drawer type	8E/4	8E/2	8E	16E	24E
Maximum number of units accepted	36	18	9	4	3

Schematic – operation switch function
Figure 4 8E/4 and 8E operating switch function

Figure 5 16E/24E operating switch function

Arrangement and combination of primary schemes
1.The total height of functional unit compartment is 72E.
2.In the same cabinet, the arrangement of functional unit :small unit is upper and big unit is lower.
3.8E/4 drawer is assemble 4 drawers to be one 8E installation unit. 8E/2 drawer is assemble 2 drawers to be one 8E installation unit. Or 2x 8E/4 and 1 x 8E/2 to be one 8E installation unit.
4.The current transformer used in the scheme is the most installed quantity in the scheme (in scheme 01-19, 21-39, can add a piece of current transformer for reactive power compensation circuit. In the real usage, it can be decreased or cancelled according to system requirements.
5.Its depth has 600mm (MCC single-side operation cabinet) & 1000mm (PC and MCC double-sides operation cabinet), we advise PC & MCC are arranged separately. When use the breaking type functional board, allow PC & MCC to be fixed installed in the same cabinet.
6.When PC & MCC are in the adjacent arrangement,
(1) When the MCC double sides cabinet (or 600 depth MCC single-side cabinet) is arranged adjacent to PC cabinet, between them ,there must add the transit cabinet (width 400mm) as the example 1 in the figure 6.
(2)When add the depth of single side MCC to be 1000mm, no need of transit cabinet ,see the example 2 in figure 6.

Example 1

Example 2