Electrical connection

Any electrical connection must securely anchor all the wires of the conductor and not place any appreciable mechanical stress on the terminal. 

The simplest form of mechanical connection is where the wire is looped round clear of the diameter of a screw and is firmly clamped by a washer under the screw head or, alternatively, by means of a washer and nut. Fig. 12.22(a) and (b). Another form is the brass pillar terminal found in plugs, sockets and lampholders, which has a hole drilled through it in which the wire is securely held by means of a brass screw. Fig. 12.22(c). 

Connection to a socket can be made by squeezing or crimping directly to the wire. Alternatively, the wire can be soldered into the socket. Fig. 12.22(d). 

Wrapped joints are used to connect wires to terminal posts. Fig. 12.22(e). The terminal post, called a wrapping post, is square or rectangular in section. Several turns of the wire are twisted under pressure round the post. 

Solder alone should not be relied upon to make a secure connection. The wire should be bent or wrapped round to give good mechanical strength and then be soldered to give the required electrical connection. Sufficient solder should be applied to enable the wire to be seen through the solder, and with just enough heat to allow the solder to flow freely round the connection (see Section 12.5). 

A second key function for adhesives is to form ohmic contacts or electrical connections between active and passive devices, connectors, leadframes, I/O leads, or other electronic parts to form a circuit. Other 

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In contrast to a direct injection of dc or ac currents in the sample to be tested, the induction of eddy currents by an external excitation coil generates a locally limited current distribution. Since no electrical connection to the sample is required, eddy current NDE is easier to use from a practical point of view, however, the choice of the optimum measurement parameters, like e.g. the excitation frequency, is more critical. Furthermore, the calculation of the current flow in the sample from the measured field distribution tends to be more difficult than in case of a direct current injection. A homogenous field distribution produced by e.g. direct current injection or a sheet inducer [1] allows one to estimate more easily the defect geometry. However, for the detection of technically relevant cracks, these methods do not seem to be easily applicable and sensitive enough, especially in the case of deep lying and small cracks. 

In reality, aircraft parts can consist of several stacked layers of material, eonnected by rivets or bolts. To avoid corrosion, the layers are often protected by a special coating, so that there is no electrical connection between the layers. If there is a crack for example in the middle layer, no current will thus flow above or below the defect because of the insulating coating between the layers. There is only the possibility for the current to flow around the crack in the x-y... 

The cell head is fabricated from a 2.54-cm steel plate and has separate compartments for fluorine and hydrogen. The oudet-gas manifolds, hydrogen fluoride feed and purge lines, and electrical connections are on top of the head. The gas separation skirt is made of Monel. An insulating gasket maintains the seal between the tank and the head. The anode assembly consists of 32 carbon blades bolted onto a copper bar, each of which contains three copper conductor posts. The cathode assembly consists of three vertical, 0.6-cm parallel steep plates. The plates surround the anode assembly and are supported by three steel posts which also serve as conductors. 

Metallization. Integrated circuits require conductive layers to form electrical connections between contacts on a device, between devices on a chip, between metal layers on a chip, and between chips and higher levels of interconnections needed for packaging the chips. It is critical to the success of IC fabrication that the metallization be stable throughout the process sequence in order to maintain the correct physical and electrical properties of the circuit. It must also be possible to pattern the blanket deposition. 

Wire Interconnect Materials. Wire-bonding is accompHshed by bringing the two conductors to be joined into such intimate contact that the atoms of the materials interdiffuse (2). Wire is a fundamental element of interconnection, providing electrical connection between first-level (ie, the chip or die) and second-level (ie, the chip carrier, or the leadframe in a single-chip carrier) packages. 

In the eady days PET mol dings were used in small components, notably electrical connections and covers for switchboxes or fuses. This is... 

Fatteiy is one or more electrically connected electrochemical cells having terminals/contacts to produce electrical energy. 

Electrical Connections. Electric current is brought from the transformers by air-cooled copper busbars and close to the electrode by water-cooled bus tubes and flexible cables, connecting to water-cooled copper contact plates at the electrode. The plates are held against the electrode by hydraulic pressure. The connectors are as short and as balanced as possible to allow cancelling of magnetic fields associated with individual conductors. 

The electrolytic cells shown ia Figures 2—7 represent both monopolar and bipolar types. The Chemetics chlorate cell (Fig. 2) contains bipolar anode/cathode assembhes. The cathodes are Stahrmet, a registered trademark of Chemetics International Co., and the anodes are titanium [7440-32-6] Ti, coated either with mthenium dioxide [12036-10-17, RUO2, or platinum [7440-06-4] Pt—indium [7439-88-5] Ir (see Metal anodes). Anodes and cathodes are joined to carrier plates of explosion-bonded titanium and Stahrmet, respectively. Several individual cells electrically connected in series are associated with one reaction vessel. 

Monopolar electrodes have a direct electrical connection with an external power supply. This requites the distribution of current over the total area of one monopolar electrode, collecting the current from the other monopolar electrode for conduction to the next cell through interceU busbars. 

Eig. 6. Options for electrical connections to parallel plate cells (a), monopolar and (b), bipolar connection. 

Busbars. Fitting the tank for d-c power is usually accompHshed usiag round copper busbars, both for supporting the anodes and the work or cathodes. Size of the copper bus is determined by the amount of current flow expected 1000 amperes requires about 6.5 cm of cross-sectional area. The bus is iasulated from the tank, and any other sources of grounding, and coimected to the d-c power supply. Shorter distances from the tank as well as fewer electrical connections keeps the voltage drop to a minimum. 

Design Principles An individual fuel cell will generate an electrical potential of about 1 V or less, as discussed above, and a current that is proportional to the external load demand. For practical apph-cations, the voltage of an individual fuel cell is obviously too small, and cells are therefore stacked up as shown in Fig. 27-61. Anode/ electrolyte/cathode assemblies are electrically connected in series by inserting a bipolar plate between the cathode of one cell and the anode of the next. The bipolar plate must be impervious to the fuel... 

Weight lo.s.s probe.s. Coupons for measuring weight loss are still the primai y type of probe in use. These may be as simple as samples of the process plant materials which have been fitted with electrical connections and readouts to determine intervals for retrieval and weighing, to commercially available coupons of specified material,... 

In certain cases, where the motor is too large and it is idle for a long period before it is installed and electrically connected (the space heaters are therefore OFF) even these heaters may not be sufficient to absorb moisture which might have condensed deep in the slots, unless, of course, the heaters are kept ON for a considerably long period. In such cases, it is advisable to heat the motor by methods 1 and 2 in addition to using the built-in heaters, until the insulation level of the windings reaches the required level. Once the motor has been installed, these space heaters, when provided in the windings, are switched ON automatically as soon as the motor is idle, and thus eliminate deep moisture condensation. 

The purpose of a flexible joint is thus to make an electrical connection and to absorb the busbar s expansion and vibrations of the generator or the transformer and to prevent transmission of these vibrations to the bus system and mounting structure. 

A cathode cable is adequate for the return path of the protection current for individual storage tanks. In pumping stations with several storage tanks, each tank must be provided with a cable connection. If the tanks are connected to each other by electrical connections, then two cathode cable connections must be provided [2]. 

Since copper-sheathed cables are also coated with plastic, the ratio of cathode/anode area (SJSJ is very small so that there is not an increased risk of corrosion of the lead-sheathed cable by the electrical connection between the cable sheathings according to Eq. (2-44). 

The railway lines on bridges are often electrically connected with steel or reinforced steel structures which usually have a very low grounding resistance. In new installations, an electrical separation of the rails from the bridge structure is required according to the grounding resistance of the structure and the type of rail bed. Independent of this, pipelines and metal sheathing of cables are always electrically separated from the structure in order to exclude direct transmission of stray current from the rails in these conductors. 

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