Electrical Arrangements

Facility electrical systems and components provide a convenient source of ignition within a hydrocarbon or ordinary occupancies whenever the design, installation or maintenance is substandard. Electrical systems or components may short, overheat, operate incorrectly, etc. These failures will present themselves as available ignition sources for hydrocarbon vapor releases. All electrical installation should be according to recognized electrical industry standards such as API RP 540 and the NEC (NFPA 70). 

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In the traditional parallel-plate cells, the Walker system is the most commonly used electrical arrangement (Fig. 13). In this system, the current flows from a copper busbar on one side of the cell to the anodes, and the cathodes are connected to another busbar on the opposing side of the cell. The second busbar feeds current to the anodes of the second cell, and so on. In the Walker system, only one side of each electrode is connected to the electric circuit. The intercell busbars do not require so much thickness as the end busbars as the current flows through the path of least resistance. 

Electrolyzers for the membrane cell electrolysis process are a filter press arrangement of cell units electrically arranged in two different cell configurations, mono-polar and bipolar. Figure 13 illustrates the examples of the electrical connection of the cells (65). Figure 14 illustrates the electrolysis... 

CIRCUIT - An electrical arrangement requiring a source of voltage, a closed loop of wiring, an electric load and some means for opening and closing it. 

A multiplier phototube consists of a light-sensitive photocathode followed by a series of dynodes arranged to multiply the electron emission from the photocathode. The electrical arrangement and basic circuitry used are described in Chapter 9. 

Fig. 3 An ultrathin membrane (e.g. BLM) separating two aqueous solutions, (a) Electrical arrangement for measuring membrane potential and current. S = switch, m = voltage supply,...

Figure 2 a) shows the case when the sample holder is empty and the piston is at the position Xo, then a field maximum is detected by diode D3. The short circuit piston must be moved to a distance 3/2X from the diode detector Dj, and the signal of Dj- being at a distance X/4 from the detector D3 - exhibits a minimum. As a result of suitable geometric and electric arrangements, the signals of the detector D2 and D4 - which are placed with X/4 spacing - are identical. The incorrect position of the short circuit piston is indicated by the difference... 

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