Terminating conductors

Slotted beam or U-contacts describe a versatile design for the termination of soHd wire and require that the wire be pushed into a narrow slot between two moderately rigid tines, or beams, at the back end of the separable contact (Fig. 8). The edges of the beams displace the insulation, squee2e the wire, and keep it in compression for the life of the connection. This termination method was developed for terminating conductors in a gang using flexible flat cables with round conductors (5). 

Which hand tools would you use for terminating conductors in a junction box ... 

The rotor body (see Fig. G-6) is manufactured from a cylindrical forging of high-alloy steel with suitable magnetic properties. A hole is driUed into the shaft extension for terminal conductors. The terminal conductors carry excitation current from the exciter to the rotor winding. 

The rectifier is built of two steel rings that are shrunk on the shaft of the exciter rotor with intermediate mica insulation. The steel rings are connected to the terminal conductors in the center of the shaft. 

The slipring shaft (see Pigs. G-14 and G-15f consists of shaft extension, insulations, sliprings, contact screws, and terminal conductors. 

The shaft extension consists of a steel forging with flange for connection to the shaft of the generator rotor. The center of the shaft extension is drilled for the terminal conductors. 

The terminal conductors in the slipring shaft and the rotor shaft are connected with contact screws. 

Electronic Applications. The PGMs have a number of important and diverse appHcations in the electronics industry (30). The most widely used are palladium and mthenium. Palladium or palladium—silver thick-film pastes are used in multilayer ceramic capacitors and conductor inks for hybrid integrated circuits (qv). In multilayer ceramic capacitors, the termination electrodes are silver or a silver-rich Pd—Ag alloy. The internal electrodes use a palladium-rich Pd—Ag alloy. Palladium salts are increasingly used to plate edge connectors and lead frames of semiconductors (qv), as a cost-effective alternative to gold. In 1994, 45% of total mthenium demand was for use in mthenium oxide resistor pastes (see Electrical connectors). 

The lead—acid battery is comprised of three primary components the element, the container, and the electrolyte. The element consists of positive and negative plates connected in parallel and electrically insulating separators between them. The container is the package which holds the electrochemically active ingredients and houses the external connections or terminals of the battery. The electrolyte, which is the Hquid active material and ionic conductor, is an aqueous solution of sulfuric acid. 

Another type of electronic connector joins coaxial conductors. These have a soHd or stranded center-conductor surrounded by a dielectric. The dielectric is covered with a conductive shield made of metal braid or tape and with a layer of insulation. Coaxial cable connectors terminate the center-conductor and the shield. These are used primarily in radio frequency circuits. The shape, dimensions, and materials of an electronic connector shell or stmcture may have to be designed to shield the connection from electromagnetic and radio frequency interferences in many appHcations. 

Fig. 8. Typical slotted beam connection where (a) is the terminal which resembles an inverted "U" (b), the wire fits loosely into the upper portion of the slot (c), the fiiimel shaped area displaces insulation and (d), the conductor extmdes into the narrow bottom portion of the slot.

The contact ends of printed circuit boards are copper. Alloys of nickel and iron are used as substrates in hermetic connectors in which glass (qv) is the dielectric material. Terminals are fabricated from brass or copper from nickel, for high temperature appHcations from aluminum, when aluminum conductors are used and from steel when high strength is required. Because steel has poor corrosion resistance, it is always plated using a protective metal, such as tin (see Tin and tin alloys). Other substrates can be unplated when high contact normal forces, usually more than 5 N, are available to mechanically dismpt insulating oxide films on the surfaces and thereby assure metaUic contact (see Corrosion and corrosion control). 

Corona A corona is generated when a highly nonuniform electric field of sufficient strength terminates on a conductor that has a small radius of curvature (i.e., a point, wire, or knife-edge). The luminous... 

Identification for equipment terminals and of terminations of certain designated conductors, including general rules for an alphanumeric system 11353/1991 BS 5559/1991 ... 

For instance, when lightning of, say, a nominal discharge current of 10 kA strikes a 400 kV (r.m.s.) overhead line, having a surge impedance of 350 Q, then two parallel waves will be produced each of amplitude 10 x 350/2 or 1750 kV which may be more than the impulse withstand level of the system and cause a flashover between the conductors and the ground, besides damaging the line insulators and the terminal equipment (Table 13.2). It is therefore imperative that the system is protected against such eventualities. 

However, they should remain insulated when terminating with an equipment or a device such as at the ends of generators, GTs, DATs or VTs. It is essential to avoid IPB longitudinal currents through the terminal equipment. Now the bellows necessarily should be of rubber. Figure 31.4(d) shows a rubber bellows but in this small part of the bellows the conductor field will not be nullified and occupy the space affecting the metallic structures, beams and equip-menl/devices in the vicinity. This needs to be taken into account at site and it should be ensured that the nearest structure, beam or equipment is at least 600 mm away from the IPB enclosure. 

Although transformers suitable for other industrial installations are generally suitable for producing applications, certain options may be desirable— primarily due to environmental considerations. At locations subject to harsh environmental conditions, and particularly at locations subject to washdown with high-pressure hoses, non-ventilated enclosures are desirable, if not necessary. Likewise, at locations subjected to salt water and salt-laden air, it often is desirable to specify copper windings and lead wires. Most manufacturers provide standard units with aluminum windings and lead wires. Even if aluminum coils are used, it is almost always desirable to require stranded copper lead wires. This will lessen corrosion and loose terminal problems when transformers arc interconnected to the facility electrical system with copper conductors. If the transformers are to be installed outdoors in corrosive environments, cases should be of corrosion-resistant material (e.g., stainless steel) or be provided with an exterior coating suitable for the location. 

The second major area for the use of plastics in electrical applications is at the terminations of the conductors. The connectors that are used to tie the wires into the equipment using the power, or used to connect the wires to the power source, are rigid members with spaced contacts. These are designed to connect with a mating unit and to the extension wires. The other type of wire termination is terminal boards where there are means to secure the ends of the wire leading to the equipment and the internal wiring in the equipment. These termination units require ... 

As a rule, electric circuits consist not of a single conductor but of several conductors connected, forming a sequence of conductors. This circuit can be closed or open. An open circuit is properly open when terminating at both ends with the same type of conductor. 

At zero current, when the potential within each conductor is constant, the potential difference between the terminal members of a sequence of conductors joined together as an open circuit is the algebraic sum of aU Galvani potentials at the individual interfaces for example. 

As in the case of an individual Galvani potential, this parameter can be neither measured nor calculated for an incomplete open circuit. But for a sequence of conductors with the same metal at either end, the obstacle pointed out in Section 2.1.4 vanishes, because potential differences between the identical terminal members can be measured. This parameter. 

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