2013年12月30日星期一

Network cabinet installation precautions

In the left rear of the cabinet, install a fully enclosed metal supply before trunking, which extends from the bottom to the top of the server rack cabinet , where the top outlet dedicated to power the fan . Mounted vertically closed metal supply duct is designed to avoid the utp cable  horizontal UTP generate power interruptions. In most of the cabinet , using an extension cord is mounted horizontally , this structure allows the spacing between the power outlet and the horizontal part of the twisted pair is less than 200mm, so it's not the ideal power distribution structure .
Rack mounted vertically in the middle of a ground copper from the low ceiling, 2U equidistant intervals on the Copperbelt an open Coarse M6 screw holes , in order to shield patch close to ground , network cabinets among the lowest end of the screw holes at the cabinet led ground. Various Network Cabinet  metal parts of the cabinet should be grounded in order to achieve the overall grounding of the cabinet, and the cabinet should be grounded through the grounding lead wire connected to the grounding copper on the room 's ground copper rafts .
Due to the increasing miniaturization of IT equipment , installation of equipment in the cabinet increased density to a station 7U blade servers , for example, a station takes about 3kVA distribution , and a 42U high rack units may be installed up to 8 such servers, the total demand will reach its distribution 24kVA. That's right cabinet power distribution system poses a severe challenge. At the same time , input and output ports of the increase , but also the reliability of the distribution system installation made ​​high demands. Taking into account the current needs of most server dual power supply , power distribution cabinet also makes more and more complicated.

2013年12月26日星期四

tend to pull the wires

Add a new home appliances, tend to pull the wires , so that the current can follow the wires into the electrical safety . Guide wire is electricity . However, the choice inappropriately wire , electrical safety operations can not . Family usually by using wire as copper or aluminum core , wrapped in a layer or layers of the surface of the insulating sheath , called the insulated wire . With this layer "coat" , even if the lamp is lit , hand to touch the wire , it will not shock . According to the hardness of the wire core is not the same , the wire was divided into hard lines and soft  lines, soft plastic wire is made ​​from a plurality of thin copper wire foreskin for frequently mobile electrical devices, such as hanging lamp lamp cord and for iron, electric rice cookers power lines. However, in moist Mini HDMI cable  places, such as walls, use insulated wire to maintain the ceiling inside the insulated wire in general , the sets of steel or plastic casing to prevent rot and leak !
Wire laying methods and addresses are not the same, the choice is not the same as the thickness of the wire . In the kitchen room and high ambient temperature corresponding to the local selection of thicker wire , installed in the pipe to maintain them . Buy a new appliance , such as a lamp , microwave ovens , etc. , all with power from a cord and plug , you might want to pull a wire when exercising in a convenient local install a patch panel , if still use thin wires generally lamps on unsafe. If power 1000 watt microwave oven , washing machine 500 watts, 300 watts iron , with the  RAC CABLE use of these appliances , then add a few times current , time use a long, thin wire resistance, poor circulation currents will result in heat and burn the wire plastic "coat ." I usually see some wire charred black plastic sheath , which is the cause of excessive current .
Thus , the increase in home appliances, should check the wiring board had entered the house power wires and line thickness . Plastic wire "coat" is used to maintain the wire , to avoid leakage use, do not use wire , lead wire hanging wires , lights, or the wire wrapped around the handles of the lead wire . Because of this the easiest to wear the wire sheath formed leakage .

2013年12月25日星期三

Wire and cable | flame retardant wires and cables | high temperature wire and cable

Over the years , China optical cable malls in 15% to 20 % annual rate of sliding scale , orientation of the wire and cable industry in China is second only to the mechanical occupation 's second largest automobile industry, China has become the largest international wire cable producer .
 However , the recent mall increasingly sophisticated global wire and cable , wire and cable manufacturing industry slowed to carry out , an increase marginally. Followed by changes in the external environment and internal competition , international wire and cable career has entered into an exclusive contest several giant format , at RAC CABLE the international aspect put the whole family . Earlier, the Chinese demand for shopping centers are almost wholly dependent on imports advanced cable . Although the number of Chinese suppliers Hongo produce up to 7,000 , but will be set at the lower level is simply the scope to compete on low quote malls, it has become the bottleneck of domestic companies to carry out . The current space in the large profitable areas of advanced cable , Chinese multinational giant mall was completely preempted .
 Because of intense competition , the primary manufacturer of wire and cable career after primary ways to reduce costs, control of fixed overhead. Followed by entry of multinationals , low price of Chinese cable professional contest will face a severe test. China wire and cable shopping for special cable receiver position is open scrimmage at the low end of a long cable company supplied a domestic withdraw the road , and like a spring breeze blowing head for the wire and cable career of this " dying patient" a needle into the "tonic . " Currently, special cables accounted for domestic cable shopping malls to sell to sell about 30% of the total , according to rough estimates the annual national specialty cable products to sell roughly 400 billion yuan. Specialty cable products shopping needs but we put up a distinction between the infinite precision stage , we demand from one to grasp , to develop, to occupy . Intense competition in general merchandise , unprofitable  HDMI CABLE today , why not focus on the development of specialty cable products . Recently, South Korea's LS Cable Group and the first global manufacturer Nexans cable company has entered Chinese market, has said that China will establish audio Anhui and Sichuan are two special cable production base , in an era of rapidly launch of specialty cable products , the will be the emergence of a number of well-deserved wire and cable companies.

2013年12月24日星期二

Terminals transformer industry in the application description and classification

Transformer is an electromagnetic induction interaction , changing the voltage , current and impedance devices. The main function of the transformer are: voltage conversion ; current conversion , impedance conversion ; isolation ; regulator (magnetic saturation of the transformer ) and the like. Classification commonly used transformers can be summarized as follows :
 ( A ) by way of cooling :
 ( 1 ) dry-type transformers : to rely on natural air convection cooling or increase the cooling fan , used for high-rise buildings , high-speed toll station electricity and local lighting , electronic circuits and other small capacity transformers . ( 2 ) oil-immersed transformers : to rely on oil as a cooling medium , such as oil-immersed self-cooled , oil -cooled , water-cooled oil , forced oil circulation.
 ( B) the winding in the form of :
 ( 1 ) two-winding transformer : used to connect two power system voltage levels .
 ( 2 ) three -winding transformer : general area substation for power systems , connecting three voltage levels .
( 3 ) auto- transformers : used to connect different voltage power systems . Can also be used as an ordinary step-up or drop after the transformer . (C ) by the core form of :
 ( 1 ) core-type transformer : used for high-voltage power transformers .
 ( 2 ) amorphous alloy transformer : amorphous alloy core transformer is new magnetic materials , load current drops to about 80% , is the ideal energy-saving effect of distribution transformers , especially for rural and developing areas such as power grids lower load rate place.
 ( 3 ) shell -type transformers : Special transformers for high-current , such as electric transformers, welding transformers ; or used in electronic equipment and television , radio and other power transformer Shanghai Hongzhi - box-type transformers.
  The new transformer terminals , terminals have been widely used in electrical and electronic engineering industries in the world : large transformers. Transformer terminals, taking into account the structural design easy wiring, screws securely connected features , you can quickly and easily installed on 2X10mm rail . Terminal products designed to meet IEC60947-7-1 and other international standards.