Electricity fittings

The purpose of testing an electrical motor is to ensure its compliance with the norms of design, material inputs and manufacturing accuracy. It determines the mechanical soundness and electrical fitness of the machine for its electrical and mechanical performance. Such tests determine the following ... 

The generic thermosets are the epoxies and the polyesters (both widely used as matrix materials for fibre-reinforced polymers) and the formaldehyde-based plastics (widely used for moulding and hard surfacing). Other formaldehyde plastics, which now replace bakelite, are ureaformaldehyde (used for electrical fittings) and melamine-formaldehyde (used for tableware). 

The use of ABS has in recent years met considerable competition on two fronts, particularly in automotive applications. For lower cost applications, where demands of finish and heat resistance are not too severe, blends of polypropylene and ethylene-propylene rubbers have found application (see Chapters 11 and 31). On the other hand, where enhanced heat resistance and surface hardness are required in conjunction with excellent impact properties, polycarbonate-ABS alloys (see Section 20.8) have found many applications. These materials have also replaced ABS in a number of electrical fittings and housings for business and domestic applications. Where improved heat distortion temperature and good electrical insulation properties (including tracking resistance) are important, then ABS may be replaced by poly(butylene terephthalate). 

Aminos. There are two basic types of amino plastics - urea formaldehyde and melamine formaldehyde. They are hard, rigid materials with good abrasion resistance and their mechanical characteristics are sufficiently good for continuous use at moderate temperatures (up to 100°C). Urea formaldehyde is relatively inexpensive but moisture absorption can result in poor dimensional stability. It is generally used for bottle caps, electrical switches, plugs, utensil handles and trays. Melamine formaldehyde has lower water absorption and improved temperature and chemical resistance. It is typically used for tableware, laminated worktops and electrical fittings. 

Phenolics. Phenol-formaldehyde (Bakelite) is one of the oldest synthetic materials available. It is a strong, hard, brittle material with good creep resistance and excellent electrical properties. Unfortunately the material is only available in dark colours and it is susceptible to attack by alkalis and oxidising agents. Typical applications are domestic electrical fittings, saucepan handles, fan blades, smoothing iron handles and pump parts. 

Uses The urea formaldehyde resins are used for domestic electrical fittings, bottle caps. These also find use for wood adhesives, surface coatings and textile finishings. 

Connectors, switches, electric distributors, fuse boxes and other electric fittings need a subtle balance of electrical and mechanical properties, durability, cost and aesthetics. This broad field creates fierce competition not only between engineering thermoplastics and SMC/BMC for the main applications but also with polypropylene and polyethylene or PVC for the lower performance parts and, at the opposite end of the scale, with high-tech plastics such as polyetherketone, polyetherimide, liquid crystal polymers. .. For example, without claiming to be exhaustive ... 

The silicon content in this bronze is about 4%. Silicon bronze has excellent resistance to corrosion by organic acids and sulfite solutions. Common uses include electrical fittings, boilers, pumps, shafts, and marine hardware. 

Elbow (ell)- A plumbing or electrical fitting that lets you change directions in runs of pipe or conduit. 

The foregoing properties account for major uses of UF in two applications, namely, bottle caps and electrical fittings. It is also used for colored toilet seats, vacuum flasks, cups and jugs, hair drier housings. 

Disposable cups and glasses for hot (only PS foam) and cold drinks, electrical fittings, CD case (jewel box), Airfix model kits, food containers, coat hangers, hair combs, TV cabinets, expanded foam packaging, foam thermal insulation, foam ceiling tiles, insulated food containers. 

Major applications Electrical fittings, telephone handsets, radio housings, cigarette boxes, lampshades, tableware, cavity wall insulation (UFFI) from 1950s until 1980 when it was discontinued due to concern over formaldehyde toxicity. 

MF plastics have lower water absorption and better durability, and they are preferentially used for tableware, laminated worktops and electrical fittings. Due to high contents of nitrogen in melamine, MF are non-flammable and can provide fire retardant properties. It releases nitrogen and formaldehyde when burned (or charred) [67]. MF foams were mainly used for fire resistant, soundproofing applications. 

Unit should be well protected from heavy rains due to high-tension electrical fittings. 

Caution There are chances of fire due to the circulating high-temperature oil, and hence, the motors, electrical fittings, and lighting must be flameproof. The pipelines, valves, gaskets, and pumps (with mechanical shaft seals) must he selected for high-temperature and high-pressure service and shall he tested as per statutory requirements. 

Ah electrical fitting, injection-moulded in PES, will operate at 150 C. It will be bolted to a steel support, and the total clamping force must not fall below 10 kN after 10 seconds. Washers with inside and outside diameters of 10 mm and 20 mm, respectivety, will be used. The maximum allowable strain for PES at 15(PC is 0.7%. Calculate the number of bolts needed, using data given in Hgures 8.13 and 8.14. 

Phenol-formaldehyde phenolic resins). A range of rather brittle, dark brown or black thermosetting resins. The original material was given the trade name Bakelite the first synthetic resin produced, it was used for electrical fittings and casings. Later variations, less brittle, are used for pump impellers, dip-pipes, agitators, and bottle closures. 

Do not tamper with faulty equipment or electrical fittings—report such faults to your supervisor. 

Irea formaldehyde Stiff, hard, strong, brittle, heat-resistant. and a good electrical insulator. Electrical fittings, adhesives... 

PPO Automotive grill fascia panels Switches, electrical fittings Ducts, light fitting housings, washing machine parts, dishwasher components... 

PET High tolerance automotive and other mouldings Electrical fittings and components ... 

The chief applications are for mechanical parts requiring resistance to wear, such as nuts, gears, and bearings chemically resistant parts, such as valve seats or jacketing on insulated wire and heat-resistant parts such as electrical fittings, sterilizable hypodermic needle holders, and hospital utensils. 

The majority of electrical and electronics waste contains PVC as it is used in electrical and electronics wiring as a sheathing material and insulator, and in electrical fittings along with other materials such as PE, polyoxymethylene, PC and so on, which form part of the waste material. 

This kind of polymer is used in molded materials (electrical fittings and kitchenware), in laminates such as Formica, in plywood and particle board as adhesive, and in foams. 

Caution Since the system works on circulating high-temperature oil, it does present a fire hazard and hence all relevant precautions must be taken for example, motors, electrical fittings, lighting must be flameproof. Besides, the pipelines, valves, gaskets, shaft seals, etc. must be suitable for high temperature and pressure and should be tested and certified. 

The pump developing high pressure for the hydrauhc oil can be located in a separate area where flame-proof electrical fittings may not be necessary. However this needs accessories like oil tank oil cooler and high pressure pump. 

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