Discussion. High Speed Motors and Dynamo-Electric Machines.

Abstract

DISCUSSION ON HIGH-SPEED NOTORS. 155Discussion.Sir FREDERICK BRAMWELL, President, in proposing votes of thanks sir Frederick to Mr. Imray and Mr. Kapp, said that the discussion on the two i + a~~l l . Papers had better be divided. First, the subject of motors would be taken, which might be divided into rotary-engines, single-acting reciprocating-engines, and ordinary double-acting engines.The next subject would be that of dynamos, under the three heads of the Hefner-Alteneck principle, the Gramme principle, and the Schuckert principle. Those matters having been treated of, what might be called the general discussion could then be entered on. H e did not suggest that a speaker, when referring to the rotaryengine, should not compare other engines with it, or that he should refrain from touching on the question of dynamos, the object being as far as possible to make the discussion systematic ; but that such system should be so far departed from as to obviate the necessity of any speaker rising a second time.in his Paper. The steam-turbine was one that he made a few years ago, after the fashion of Mr. Froude's liquid brake. There were a number of ratchet-cells in the circumference of the wheel, each of these cells being semicircular in section, and there were corresponding cells in the shell. The steam entered and was supposed to play in a sort of vortex into one cell of the wheel, out of that into the wheel-casing, and so on, following a vortical movement all round until it issued at the outlet. The machine exhibited was what was actually driven. The usual speed was 12,600 revolutions per minute, but 12,000 was about the best. There was attached to it a €riction-brake carrying a weight, so that the power could be calculated.He measured the quantity of steam exactly, and found that it was not economical, using twice as much steam as an ordinary high-pressure-engine. Another specimen of rotary-engine was Mr. Tower's ingenious machine. It was a universal joint enclosed in a spherical shell, with expanding and contracting cavities. I n Mr. Fielding's engine there was also a sort of universal joint, four pistons working in four segments of bent pipe (they could not be called cylinders) upon curved axes. One advantage claimed for it was that the packing was of the ordinary spring-ring kind. He also exhibited one of the engines used in the fish-torpedo by Mr. Brotherhood. It was worked by compressed air. There was also a model of Mr. Brotherhood's com- Mr. GIS~ERT EAPP directed attention to the diagrams illustrative of his Paper, showing that different kinds of field-magnets had been drawn for the same diameter of armature, so as to give an approximate idea of the difference in bulk and weight between the different types of machines. The idea was only approximate, because the same-sized armature in one type might be much more efficient than in another type. Amongst the diagrams there were three different kinds of magnet, which were fairly representative of three types of dynamos used by him under certain conditions. Plate...