Electric supply

Assumes deUvered electricity has one-third of the energy content of the fuel used to produce it ie, 1 Joule of electrical supply to an industrial user represents 3 Joules of fuel consumed. 

Protection of the electrical supply system in the event of a motor or motor-feeder short circuit. The fault must be cleared from the rest of the system to prevent further trouble,... 

Recommended practice for inductive coordination of electrical supply and communication lines... 

The current needed for cathodic protection by impressed current is supplied from rectifier units. In Germany, the public electricity supply grid is so extensive that the CP transformer-rectifier (T-R) can be connected to it in most cases. Solar cells, thermogenerators or, for low protection currents, batteries, are only used as a source of current in exceptional cases (e.g., in sparsely populated areas) where there is no public electricity supply. Figure 8-1 shows the construction of a cathodic impressed current protection station for a pipeline. Housing, design and circuitry of the rectifier are described in this chapter. Chapter 7 gives information on impressed current anodes. 

A speed controller synchronizes the expander/generator with the electricity supply grid, and actuates the inlet trip valve to its fully open position. 

Work on high-voltage electrical supply, radioactive equipment, roof work such as checking toxic exhaust from ventilation outlets. 

Bee.iusa the nitrogen pressure was unreliable, it was difficult to maintain a pressure of 0.5 inch water gauge in the metal cabinet. Workers complained that the safety switch kept isolating the electricity supply, so an electrician reduced the setpoint first to 0.25-inch and then to zero, thus effeciocly bypassing the switch. The setpoint could not be seen unless the cover of the switch was removed and the electrician told no one what he had done. The workers though I lie wa,s a good electrician who had prevented spurious trips. Solvent and air leaked into the cabinet, as ilready described, and the next time the electricity supply was switched there was an explosion. 

The air velocity through a heater battery should be to the manufacturer s rated output within its range of safe temperatures. In large units the electrical load is balanced across the three phases of the electrical supply. 

Electricity supply, voltage, and phase and whether a standby supply is required... 

The basic reasons for grounding an electrical supply system are to limit the electrical potential difference (voltage) between all uninsulated conductive equipment in the area to provide isolation of faults in the system and to limit overvoltage on the system under various conditions. In the case of a grounded system it is essential to ground at each separately derived voltage level. 

When an electrical supply has been isolated, it is normal practice to check that the right switches have been locked or fuses removed by trying to start the equipment that has been isolated. However, this system is not foolproof, as shown by the following incidents. 

Ontario Hydro. (1998). Ice Storm 98 Electricity Supply Impacts of the Januaiy 1998 Ice Storm in Eastern Ontario. Toronto Author. 

Arrotlier poterrtial problem for hydroelectricity is the possibility of electricity supply disruptions. A severe drought can mean that there will not be enough water to operate a hydroelectric facility. Communities with very high dependence on the hydroelectric resources may find themselves struggling with electricity shortages in the form of brownouts and black-outs. 

The second type of hydroelectric plant is called a run-of-the-nver system. In this case, the force of the river current applies pressure to the turbine blades to produce electricity. Run-of-the-river systems do not usually have reseiwoirs and cannot store substantial quantities of water. As a result, power production from this type of system depends on the river flow— the electricity supply is highly dependent upon seasonal fluctuations in output. Run-of-river projects are most successful when there are large flows in flat rivers or when a high natural geological drop is present, and when the required electricity output is below the maxiniuiii potential of the site. 

By the early twentieth centui y, hydroelectric power was providing more than 40 percent of electricity generation in the United States. In 1940, hydropower supplied about three-fourths of all the electricity consumed in the West and Pacific Northwest, and still supplied about one-third of the total U.S. electricity supply. Although hydroelectric-ity s share of total electricity generation has since fallen to about 10 percent in the United States, hydro-electricity provides almost one-fifth of the world s total electricity generation today. 

Energy systems in space technology are devices that convert one kind of energy into another to ensure the functioning of automated and piloted satellites, interplanetary probes, and other kinds of spacecraft. Multiple functions of any spacecraft require two distinctly different energy sources propulsion for launch and maneuvers, and electricity supply to power the onboard equipment. 

Previous considerations concerning the purpose engineering of the facility will have established the size and characteristics of the electrical load in terms of consumption and maximum demand. These will be essential data with which to inquire of the electricity authority as to the availability of an electrical supply. 

An electrical switchgear panel that provides an electrical supply to each elevator machine. 

Have a separate emergency electrical supply and feeder cable ... 

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