Standard Electric Glow Lamps

    Abstract

    THE report of the Engineering Standards Committee on the British standard specification for carbon filament glow lamps, which has recently been issued, is of great interest, more especially as it has been published at a time when so many important papers and discussions on carbon and metallic filament lamps are occupying the attention of men of science and engineers. The specification gives at the beginning a list of standards and definitions, and goes on to state what the committee has decided as to the tests a standard lamp shall comply with. A lamp of 12 candle-power is suggested in addition to the usual 8, 16, 25, and 32, and this should prove a very useful size; although it has already been used, it has not been kept as a stock lamp usually. The standard lamps are to b divided into two classes, having a useful life of 400 and 800 hours respectively, and all lamps purporting to be British standard lamps are to be marked with the trade mark or name of manufacturer, the standard mean horizontal candle-power, the voltage, and a reference letter in a circle, which is to show which class—whether 400 or 800 hours—the lamp is intended for. This reference letter is, we think, a mistake, as the ordinary consumer will not know to what it refers, and we do not see the objection to marking plainly on the lamp the useful life hours. The insulation resistance between cap and filament seems to us to be rather high (1000 megohms). The limits for mean horizontal candle-power and total watts, on the other hand, allow plenty of margin, but doubtless these will be reduced after the standards have come into force, which we understand they will do in July next. At present, however, we do not see that the ordinary consumer will benefit very greatly by the specification when it does come into force, for, as we pointed out a few months back, unless the borough councils or local authorities erect special testing laboratories where tests on lamps cah be carried out by an expert for a very small fee, or even free of cost, the ordinary consumer will be in practically the same position as he is at present. Of course, the fact of his being able to ask for a standard lamp may tend to make the article sold him slightly better, and with truer candle-power and consumption figures marked on still, we are afraid that, from the consumers point of view, until he can get his lamps tested locally, not very much improvement will be seen. The report is, however, of very great interest to those connected with that branch of the electrical profession, and is certainly a long step in the right direction.

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    Standard Electric Glow Lamps . Nature 75, 380 (1907). https://doi.org/10.1038/075380b0

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