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1000V Aerial Bundled Cable Service Drop Cable.http://zmscable.com/0.html

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What is Magnet wire/ enameled wire ?

Magnet wire or enameled wire is a copper or aluminium wire coated with a very thin layer of insulation. It is used in the construction of transformers, inductors, motors, speakers, hard disk head actuators, electromagnets, and other applications that require tight coils of insulated wire.

The wire itself is most often fully annealed, electrolytically refined copper. Aluminium magnet wire is sometimes used for large transformers and motors. The insulation is typically made of tough polymer film materials rather than enamel, as the name might suggest.

Construction

Conductor

The most suitable materials for magnet wire applications are unalloyed pure metals, particularly copper. When factors such as chemical, physical, and mechanical property requirements are considered, copper is considered the first choice conductor for magnet wire.

Most often, magnet wire is composed of fully annealed, electrolytically refined copper to allow closer winding when making electromagnetic coils. High-purity oxygen-free copper grades are used for high-temperature applications in reducing atmospheres or in motors or generators cooled by hydrogen gas.

Aluminium magnet wire is sometimes used as an alternative for large transformers and motors. Because of its lower electrical conductivity, aluminium wire requires a 1.6-times larger cross sectional area than a copper wire to achieve comparable DC resistance.

Insulation

Although described as "enameled", enameled wire is not, in fact, coated with either a layer of enamel paint nor with vitreous enamel made of fused glass powder. Modern magnet wire typically uses one to four layers (in the case of quad-film type wire) of polymer film insulation, often of two different compositions, to provide a tough, continuous insulating layer. Magnet wire insulating films use (in order of increasing temperature range) polyvinyl formal (Formvar), polyurethane, polyamide, polyester, polyester-polyimide, polyamide-polyimide (or amide-imide), and polyimide.

Polyimide insulated magnet wire is capable of operation at up to 250 °C. The insulation of thicker square or rectangular magnet wire is often augmented by wrapping it with a high-temperature polyimide or fiberglass tape, and completed windings are often vacuum impregnated with an insulating varnish to improve insulation strength and long-term reliability of the winding.

Self-supporting coils are wound with wire coated with at least two layers, the outermost being a thermoplastic that bonds the turns together when heated.

Other types of insulation such as fiberglass yarn with varnish, aramid paper, kraft paper, mica, and polyester film are also widely used across the world for various applications like transformers and reactors. In the audio sector, a wire of silver construction, and various other insulators, such as cotton (sometimes permeated with some kind of coagulating agent/thickener, such as beeswax) and polytetrafluoroethylene (Teflon) can be found. Older insulation materials included cotton, paper, or silk, but these are only useful for low-temperature applications (up to 105°C).

For ease of manufacturing, some low-temperature-grade magnet wire has insulation that can be removed by the heat of soldering.[4] This means that electrical connections at the ends can be made without stripping off the insulation first.

Cross-section

Smaller diameter magnet wire usually has a round cross-section. This kind of wire is used for things such as electric guitar pickups. Thicker magnet wire is often square, rectangular or hexagonal (with rounded corners) in cross section, packing more efficiently and having greater structural stability and thermal conductivity across adjacent turns.

Classification

Like other wire, magnet wire is classified by diameter (AWG number, SWG or millimeters) or area (square millimeters), temperature class, and insulation class.

Breakdown voltage depends on the thickness of the covering, which can be of 3 types: Grade 1, Grade 2 and Grade 3. Higher grades have thicker insulation and thus higher breakdown voltages.

The temperature class indicates the temperature of the wire at which it has a 20,000 hour service life. At lower temperatures the service life of the wire is longer (about a factor of 2 for every 10 °C lower temperature). Common temperature classes are 105 °C, 130 °C, 155 °C, 180 °C and 220 °C.

Current density

In practice maximum current density can vary from 2.5 A/mm2 for a wire isolated from free air to 6 A/mm2 for a wire in free air.[citation needed] If the wire is carrying high frequency currents (above 10 kHz) the skin effect may affect the distribution of the current across the section by concentrating the current on the surface of the conductor.

If active cooling is provided by blowing air or circulating water much higher current densities can be achieved - proportionally to the effectiveness of cooling.

An aluminium wire must have 1.6 times the cross sectional area as a copper wire to achieve comparable DC resistance. Due to this, copper magnet wires contribute to improving energy efficiency in equipment such as electric motors.

Applications

Magnet wire is used in windings of electric motors, transformers, inductors, generators, headphones, loudspeaker coils, hard drive head positioners, electromagnets, and other devices.

http://www.zmscable.com/news/1155.html

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Have you seen the future of Underground cable?

Underground cable is the cable designed to be place underground, either directly buried or in conduit. Underground cable must be specially designed to protect against moisture, rodents, cable-seeking backhoes, and other earth-moving equipment. The underground cables are classified in two ways; by the voltage capacity, or by the construction. By Voltage LT cables: Low-tension cables with a maximum capacity of 1000 V HT Cables: High-tension cables with a maximum of 11KV ST cables: Super-tension cables with a rating of between 22 KV and 33 KV EHT cables: Extra high-tension cables with a rating of between 33 KV and 66 KV Extra super voltage cables: with maximum voltage ratings beyond 132 KV By Construction Belted cables: Maximum voltage of 11KVA Screened cables: Maximum voltage of 66 KVA Pressure cables: Maximum voltage of more than 66KVA Compared to overhead cables, underground cable have the following advantages: 1. Less subject to damage from severe weather conditions (mainly lightning, wind and freezing) 2. Reduced range of electromagnetic fields (EMF) emission, into the surrounding area. However depending on the depth of the underground cable, greater emf may be experienced.[2] The electric current in the cable conductor produces a magnetic field, but the closer grouping of underground power cables reduces the resultant external magnetic field and further magnetic shielding may be provided. 3. Underground cables need a narrower surrounding strip of about 1–10 meters to install (up to 30 m for 400 kV cables during construction), whereas an overhead line requires a surrounding strip of about 20–200 meters wide to be kept permanently clear for safety, maintenance and repair. 4. Underground cables pose no hazard to low flying aircraft or to wildlife. 5. Much less subject to conductor theft, illegal connections, sabotage, and damage from armed conflict. 6. Burying utility lines makes room for more large trees on sidewalks, which convey environmental benefits and increase property values. While the underground cable is also having such disadvantages as more expensive, difficult in identifying, repairing broken cables and damage to cables or electrocution may occur to people digging the ground and if they are unaware of the cable’s existence. To avoid artificial damage, people usually install the underground cable marker. Markers are put at regular intervals to show the route and warn of the hazard of digging into the cable. On the whole, Underground cable is the replacement of overhead cable In the place of densely populated or land is costly or environmentally or aesthetically sensitive, The advantages can in some cases outweigh the disadvantages of the higher investment cost, and more expensive maintenance and management. Now more and more developed countries are choosing the underground cable. All low and medium voltage electrical power (<50 kV) in the Netherlands is now supplied underground. Other EU countries such as the UK and Germany are undergrounding a portion of their cables each year. In the United States, the California Public Utilities Commission (CPUC) Rule 20 permits the undergrounding of electrical power cables under certain situations.

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Collecting Oil Sample from Oil Immersed Electrical Equipment

Process of Collecting Oil from Oil Immersed Electrical Equipment Like Transformer. We collect oil sample for performing different tests on the oil to determine different physical, chemical and electrical characteristics of the oil. The sample is the representative of the oil inside the equipment. That is why, we take special care during collecting oil sample from the equipment. Otherwise surrounding atmosphere may affect the characteristics of the oil which may differ the outcome of the tests form the actual results.

The normal procedures of collecting oil from a transformer or other oil immersed electrical equipment are given in following points

   1.We should always take at least 1 to 2 liter of oil from bottom valve or oil sample valve (if available) depending upon the tests to be performed on that sample.

   2.We should ensure that sampling is done by well experienced technical personnel.

   3.We should not take sample of the oil in rainy, stormy, foggy, and snowy weather since it can affect the water contaminant of the oil. We should also avoid oil sampling in high atmospheric humidity for same reason.

   4.We should use dry and clean containers preferably made of amber colored glass or clear glass or seamless stainless steel bottle. We can also use plastic bottle provided its suitability has been approved.

   5.First we should run of some of the oil from oil sampling valve of the equipment to ensure the removal of any contaminants in the orifice of the valve.

  6.Before toping up the bottle, we should rinse the sampling bottle with some oil

   7.We should fill the bottle slowly and gently. We should allow the oil to flow against the wall of the bottle to avoid any formation of air bubble in oil so that no air can be trapped in the sample.

   8.We should fill the bottle up to 95% of its capacity

   9.Now we carefully close the bottle.

   10.We must avoid any adisive tape like thing at the cover.

   11.Now, the bottle must be labeled with

       .Name of the equipment from where sample is collected

       .Rating of the equipment

       .Serial No of the equipment

       .Installed location of the equipment

       .Other identifications of the equipment if required.

       .Temperature of the oil at the time of collection

       .Date of collection

       .Identification of the sampling point (whether it is from top or bottom)

   12.If we collect the sample oil in clear glass bottle, we should keep in in dark place.

http://www.vericable.com/cables/insulatedwire/metallic-shielded-wire.htm

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Electronic Appliance Wire

With excellent resistance to heat, cold and varnish thanks to Furukawa’s proprietary materials technologies, BEAMEX wires are used in all manner of fields, including electronic devices and motors. In addition to our highly flexible SOFLEX and ECOSOFLEX wires, we also offer halogen-free wires that contain no PVC, plasticizers, antimony, or other hazardous substances. These products are compliant with UL and CSA standards and the Electrical Appliance and Material Safety Law.

Automobile Wire (JASO specifications Wire etc.)

   Our range includes AVX, AVSSX, AEX, and AESSX wires that are compliant with JASO standards. Our AESSX wires are halogen-free and contain no halogen-based flame retardants, plasticizers, antimony, or other hazardous substances.

   We also manufacture, under individual specifications, automobile cables capable of resisting temperatures of at least 120°C.

http://www.vericable.com/cables/insulatedwire/Flexible-wire.htm

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Opening ceremony of Int'l #Army Games 2017  held in Korla of NW China's