Detailed Product Description

MNS system is a plant-assembled low voltage switching cabinet unit,and its technical indexes meet IEC439-1.MNS series low-voltage switching cabinet involves fixing technology and drawer technology.The selected materials involve steel plate structure technology and permissible structure technology.Itstechinal level has reached the internal level in the eighties.MNS system can meet the requirement for power stations,ships,oil platforms and industrial and mining enterprises for power distribution systems.

Technical characteristics

1.     configuration

the switch cabinet is equipped with high strength enclosure and the frame is assembled with C sectional bars.The C sectional bars is bended fron the steel sheets with open holes(modules E=25mm).The entire cabinet frame and the inner layer clapboard are painted with oil paint.

Motor control center cabinet:the cabinet is assembled with drawers of different size.Main switch for each main circuit is high disjunction plastic shelled breaker orload switches with rotary fuse.

Five kinds of drawer units can be assembled singly in one cabinet,or mixed.the maximum number of units installed singly in one cabinet is listed in Table2.

MCC cabinets can be assembled into singlesided operation cabinets or double-sided cabinets according the using conditions.each cabinet can be divided into 3 compartment and cable compartment.

One thermal insulating polyurethane plastic plate is installed between the main bus-bar compartment and electric compartment for each compartment.the plate is used to avoid flasing over caused by failure of switch components and accident occurred between bus-bars.

Galvanized plates with vents are used to separate the drawers on different floors.fire-resistant engineering plastic parts are used to insulate the circuits for little 8E/4,8E/2 drawers.

Many kinds of plastic components are used to hold the live parts in the cabinet.Those components are made of non-haloid materials and have insulating preperty of CT1300 degree.

Two groups of bus-bars can be equipped for MNS switch cabinet and installed in the back bus-bar compartment.the bus-bars can be installed on the bottom of the cabinet back respectively.the top and bottom bus-bars can be made of materials with different

Sectional area according to the using conditins.both of them can be supplied singly or paralleling,and can also be used as reserve power supply.

Power distribution bus-bar(vertical bus-bar) is assembled in the fire-resistant plastic plate to avoid discharge caused by arc or contacting with human body.The bus-bar is connected with main bus-bar through special joint.independent PE grounding and N neutral conductor are installed on the bottom and right side of the cabinet through the whole device.Groundings and zero line connection for each circuit can e near connected. The frame is connected with self-threading screw to ensure the reliability for grounding.

 The layout in the switch cabinet must be reliable,safe,and proper and can meet the using requirement.enough space is left for manufacture,connection and maintenance of cable head.

Movable portage lifting bolts are provided in the switch cabinet for transportation and portage of switch cabinet.

Protection degree of switch cabinet is IP30(IP40).

2.     main bus-bar and branch bus-bar

bus-bars are made of copper with high conductionce.bus-bar bridge has the same cross section as main bus bar.at least 2 bolts are needed for each joint when conneted by bolts.

Main bus bar frame and bus bar insulating materials have the characteristics of low moisture absorption and will not depress the mechanical and dielectric strength of equipment.

All the copper bus bars are coated with tin in the canbinet and the lap jointed parts of the bars are embossed.insulated hot shrinkage tubes can be used to pack the bare part according to the users need.

Neutral bus nar N,the rated current value should be equal or larger than 50%.

3.     lead wire of auxiliary circuit

insulated voltage should be larger than 500v for lead wire in auxiliary. And the cross sectionof copper wire should be larger than 2.5mm2 for current circuit,1.5mm2 for control circuit and 1.0mm2 for signal circuit.

Fire-resistant terminal lines with rated voltage of 500v are used as secondary terminal lines. And each terminal line has been numbered.

4.     protection grounding

grounding bus bars(PE) are installed on the bottom through the entire equipment in the switch cabinet.modulus has been extruded for N and PE bus bars in cable compartment.The N and PE bus bars are installed bertically and fixed with insulator.

Cross section of neutral conductor N bus bars meets GB7251.1-1997.

The protection grounding circuit of the device should be constituted with independent protection grounding bus bars and conductiong structure to ensure the electrical continuality among the bare conductors and protection grounding circuit.all the metal clapboard used to isolate the live parts should be grounded effectively.

Protection grounding bus bar should be able to withstand the mechanical stress caused by transportation and installation and mechanical stress and thermal stress by singlephase grounding shorting out.