Electrical housings

Polyesters exhibit excellent electrical properties. They resist breakdown when exposed to continual electrical loads and have a high electrical resistance. For this reason, they are often used in electrical housings, as insulating films in electrical components, and as wire insulation where high temperatures are likely to be encountered. 

Typically, polyester resins are used for high-end applications that require excellent electrical and thermal resistance. When dimensional stability under load is more critical, glass fibers are incorporated to increase the heat distortion temperature and the stiffness of the part. Examples of glass fiber reinforced parts include electrical housings, electrical adapters, computer components, telephone housings, and light bulb sockets. When impact modified, polybutylene terephthalate can be injection molded to make car bumpers. 

What properties make polyesters excellent for electrical housing applications ... 

Electrical housings may be purged with an inert gas or air that flows at a sufficient rate to dilute the atmosphere immediately around an energized circuit so that atmospheric released gases will be... 

Some electrical properties of reinforcing fibers, composite resins, and the resulting composites are given in Tables 6.12, 6.13, and 6.14, respectively. These values should be taken as approximate only, especially for the composites, since fiber orientation, content, and field strengfh have an enormous impacf on fhe dielecfric properties of these materials. Some of the most widespread electrical applications for glass-fiber-reinforced epoxy systems are in printed circuit boards and electrical housing such as junction boxes. 

Glass-reinforced SMA polymers are used as electrical connectors, consoles, top pads, and as supports for urethane-padded instrument panels. There are seveial additional automotive uses. SMA aie also found in coffee makers, steam curlers, power tools, audio cassette components, business machines, vacuum cleaners, solar heat collectors, electrical housing, and fan blades, among others. 

VINYL CHLORIDE POLYMERS. Poly(vinyl chloride) (PVC), commanding large and broad uses in commerce, is second in volume only to polyethylene, having a volume sales in North America in 1995 of 6.2 x 109 kg(13.7 x 109 lb). Vinyl compounds usually contain dose to 50% chlorine, which not only provides no fuel, but acts to inhibit combustion in the gas phase, thus supplying the vinyl with a high level of combustion resistance, useful in many building as well as electrical housings and electrical insulation applications. 

MAJOR PRODUCT APPLICATIONS textiles, coatings, nonwovens, adhesives, fibers (carpet, draperies, clothing), polyester laminates, wallcoverings, wire insulation, office furniture, automotive interiors, electrical housings, computers, printers, appliances, telecommunication, film, sheet... 

Electrical Trim- Work performed by the electrical contractor when the house is nearing completion. The electrician installs all plugs, switches, light fixtures, smoke detectors, appliance "pig tails", bath ventilation fans, wires the furnace, and "makes up" the electric house panel. The electrician does all work necessary to get the home ready for and to pass the municipal electrical final inspection... 

Jumpers- Water pipe installed in a water meter pit (before the water meter is installed), or electric wire that is installed in the electric house panel meter socket before the meter is installed. This is sometimes illegal. 

PPE/PS Noryl/General Electric Improved processing, combination of heat resistance, excellent dimensional stability and toughness Computer and business equipment housings, automotive instrument panels, interior trim, connectors, electrical housings, medical components... 

Moided secondary components, substitution for metal castings, electrical housings, and parts. Complex electrical components, leading and trailing edges, and highly loaded complex shapes. Primary and secondary structure for subsonic aircraft, ducts, housings, bulkheads, intake manifolds, helicopter blades, radomes, etc. (Probably the most versatile material)... 

Microcrystalline cellulose electrical goods, household Poiyaryiate resin electrical housings Polybutyiene terephthaiate... 

Chopped glass/polyester Molded secondary components, substitution for metal castings, electrical housings, and parts. 

Poly(ether imide), PEI. Applications electrical housings, sockets, microwave parts, bearings, gear wheels, automotive parts. 

Electrical output (gross) Electrical house load Heat output... 

St3roblend FR KR 2720 - high impact, halogen-free, heat distortion resistant, V-2 (electrical housings such as TV sets, rear covers of TV, computer system housings)... 

Consumer electronics, telecommunication components, computer housings, instrument and electrical housings, and business machines. 

Nylons are often used in electrical products, such as electrical connectors, terminal blocks, smah electrical housings, switch components, wire ties, and other industrial parts, where thermal stability and fire resistance are priorities. Because of this practical interest, the thermal stability and flame retardancy of nylons have been studied extensively. Halogen compounds are effective flame retardants for polyamides [14-17], but they have limited utility because their combustion products are toxic. Alternative flame retardants are used with polyamides, such as phosphorus- and nitrogen-containing substances. The most important organic nitrogen-containing flame retardants are melamine and its derivates [14, 18-20]. However, these traditional flame retardants are outside the scope of this chapter. 

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