This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1896 Excerpt: ...number of offices in it where light is only wanted until six or seven o'clock; while in a residential district possibly all the lamps in the house are only alight for a very short time, say when people are dfessing for dinner. Thus we find that at West Brompton, which is almost entirely a residential district, the ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1896 Excerpt: ...number of offices in it where light is only wanted until six or seven o'clock; while in a residential district possibly all the lamps in the house are only alight for a very short time, say when people are dfessing for dinner. Thus we find that at West Brompton, which is almost entirely a residential district, the proportion of lamps alight to lamps wired never exceeds 45 per cent, whereas the St. James's and Pall Mall Company, who supply Piccadilly, Regent Street, Pall Mall, etc., often have 75 per cent, of the number of lamps wired alight. Engineers are very fond of studying what are termed "loadcurves." In these a sheet of squared paper is taken, and equal distances along the horizontal line are marked to represent equal intervals of time. Equal distances plotted along the vertical line represent equal increases of current, or, what comes to the same thing, equal increases in the number of lamps alight. If a number of points are found representing what the output of the station is at different times, and these points are joined, we get an irregular curved line, which forms a graphical representation of the work done by the station machinery. An illustration, printed by the publishers of the Electrician, shows the output of one of the St. James's Company's stations during two foggy days. It will be noticed how short the period of maximum demand really is, and under what may be termed normal conditions it becomes very much less. A district where late hours are kept, and where the demand is spread over a long period rather than being very heavy for a short time, is desirable for successful central station work. Scattered villadom requires very careful planning. It is a well-known engineering fact that steam engines work under their most satisfacto...
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