Enameling wire

Wire coating Wire, corded Wire covering Wire, electrical Wire enamel Wire insulation Wire materials Wire-rope machines Wires... 

Email-belag) m. coating of enamel, -draht) n. enameled wire, -farbe)/. enamel color, -ge-fiisS) n. enameled vessel. -glaS) n. enamel glass, fusible glass, -lack, m. enamel varnish, enamel. 

Plugs for graphite bridge initiators are made by molding the plastic about a twisted pair of enameled wires, and thea grinding the surface clean, bis ieaves a plastic surface with two metal islands separated by twice the thickness of the enamel. A droplet of colloidal suspension of graphite in water is applied over the point of closest approach of these islands to dry. Since both resistance... 

Each switch is composed of a pair of fine Cu wires stretched tightly by means of a clamp on the outside of containing tube. The spacing betw wires is regulated to a few multiples of the maximum grain size. In order to avoid premature operation ofr the switch by means of photo-ioni zation, enameled wires are used. In case of liquid expls, the arrangement represented in Fig... 

The evaluation of these materials as wire enamels must be made on the basis of tests performed on insulated wire. A laboratory enameling machine has been built that can produce hundreds of feet of enameled wire suitable for testing. 

Work on improving the thermal resistance and particularly the resistance to carbonization (short circuiting of layers of enameled wires under the influence of temperature) via special glycols led to diphenols [29,30]. Diphenols are not reactive under the conditions of a normal poly(ester-imide) synthesis. In synthesis the lower aliphatic diesters of diphenols were used [29-32]. The use of acid chlorides in the polyester reaction with aromatic OH-groups was also protected by patents [33-35] but it seems unlikely that this reaction was performed on the production scale. 

The water based poly(ester-imide) wire enamel from Table 3 has the same resin composition as the cresol free solvent based resin 2. It can be seen that the mechanical and thermal properties of the water based varnish are inferior to the noncresylic product. It was also found that minor amounts of drawing agent residues from copper wire manufacturing were highly detrimental to the surface quality of the enameled wires. 

Smooth running of the wire is one of the essential requirements for producing high-grade enameled wires and preventing cracks. 

The suitability of an enameled wire for a particular application depends to a very large extent on the thermal class to which it belongs. Classification of a wire according to the usual IEC standards is carried out primarily on the basis of its temperature index, breakdown voltage at nominal temperature, and the heat shock characteristics of the insulation. The IEC specifications are internationally binding. In many countries the national standards are completely IEC-harmo-nized. 

Besides the manufacturing of enameled wires in a conventionally way, starting from copper wire and a solvent-based varnish, other technologies have been developed. 

Solderable wires are used in telecommunications and the construction of analytical instruments, but they are becoming more and more common in small motors and dry-type transformers. The special characteristic of solderable wire enamels is the direct soldering. When the enameled wire is dipped in a solder bath at temperatures above 350 °C the coating melts and leaves the bare copper wire, avoiding the need for elaborate mechanical or chemical removal of the enamel. This characteristic achieved in solderable poly(ester-imide) by a special polymer composition and in polyurethane based wire enamels is due to the thermally reversible splitting of the polyurethane group. Nevertheless, good thermal stability is necessary and product temperature indexes >155 are required. For temperature indexes of 130, simply polyurethane wire enamels were used. 

Long-term behavior of insulation systems can be estimated after the temperature index has been determined by the impregnated twisted pair test (IEC 172, criterion breakdown voltage) or helical coil test (IEC 1033, Method B, criterion bond strength). The two tests lead to differing results that do not correlate and the end user of the system enameled wire/impregnating resin has to decide which test is applicable for his electrical appliance. It is important to choose a suitable combination of materials and to ensure close cooperation between manufacturers of electrical insulating materials and those who later process them. 

Fig. 20. Coil piece using rectangular enamelled wire.

Only a limited number of such leads can be mounted on an electrical high-pressure plug. Alternative methods can be used to introduce many leads on a small-diameter plug, such as that shown in Fig. 3.3 more than ten individual enamelled wires can be embedded in an insulating conical shell made of an epoxy and elastomer resin which has been used above 3 GPa. Special lead-... 

The aim of the present study is the investigation of activity of the catalysts based on foam materials (foam metals and foam ceramics) in the processes of deep oxidation of volatile aromatic compounds and neutralization of gas emissions of enameled wire production. 

Foam Pd/Nichrome and LaCoOs/ceramics catalysts can be recommended for neutralization of gas emissions of enameled wire production. 

H. Kikuchi, H. Hanawa, Y. Honda, Development of polyamide-imide/silica nanocomposite enameled wire. Electron. Comm. Jpn. 96, 41-48 (2013)... 

A two part silver conductive adhesive (EPOTEK H20E) and a paint brush (Fig. 5.4) were used for connecting the pads via enameled wires to connection sockets. The wire pieces are stripped at both ends and are fixed by sticky tapes on a connection setup. 

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