[PT032AAD2], Technical Note, Thomas Alva Edison, May 14th, 1887



The object of this invention is to obtain Motive power from heat. The invention consists in causing heat to act upon a rotating cylinder formed of iron which is magnetized and rotates in a magnetic field in such a manner as to produce a dysymetry of the lines of force. The heat reducing or destroying (in a certain portion of the cylinder) The magnetism for the time being. Advantage of the known fact that the capacity of iron for magnetism diminishes by heat & practically disappears at a bright red heat. Mounted on a shaft is a bundle of thin iron tubes, nickel plated or covered with a thin coating of enamel to prevent oxidation. The tubes are made thin so as to gain & lose heat quickly They are placed longitudinally around the main shaft, and form a cylinder the whole being secured by bands & plates to the cylinder-- At both ends the cylinder of tubes are open except at each end two fixed plates. These plates do not rotate with the shaft but are fixed and their inner face towards the cylinder just rest & rub against the end of the tubes. At the ends B&C the plate is so arranged that it covers all the central portion of the tubes as in fig 3. D is a furnace or fire box. The flame or hot air passing up through the flues EE' the ends of these flues just touch the ends of the tubes & cover the portion of the tubes not covered by the plates B.&C. at the opposite end are also two flutes and the flame or hot gases pass from them to the chimney or to the furnace of another similar motor. The cold air inlet is at the plate C. The air enters and passes through all the tubes covered by the plates B&C but not by the flues EE' gg' when the air reaches the plate B it passes down through a flue to the furnace. This air becomes heated in the passage & serves three purposes first to reduce the temperature of the iron tubes & thus increase their capacity for magnetism & 2ndly to utilize the waste heat & 3rdly to quicken the alternate heating & cooling of the iron & consequently increase the speed & power of the motor [drawings figs 1-3 follow] fig 1 shows the lines of force when the two sides of the cylinder is heated The armature is magnetized by a fixed coil N fig 1 wound as shown in fig 4 [drawing] This coil is formed of rods insulated from each other by porcelain or other infusible washers containing such a number of holes as there are convolutions. This coil & the wire in the field magnet are connected in series. I preferably use a very few turns of large copper wire on both field & fixed coil & enegizing the same by a current of many amperes rather than use a great number of turns & small number of amperes by this means I am enabled to insulate the whole system by infusible washers or material The fixed coil may be dispensed with and the inlet & outlet flues arranged as in fig 5 [drawing] but the motor is not so powerful-- The field of force may be a permanent magnet for a small motor but for large ones I prefer to use electromagnets. The fields & fixed coil are to be energized by an auxilliary Dynamo worked by the motor itself The initial start of this Dynamo being given by hand; Claim-- A prime motor substantially as described. Dyer isnt the above claim a goon one in law & isnt the broadest kind of claim for court construction should anyone use this principle if not make usual claims-- This principle is absolutely new the power is not very great but I hope to do something with it patent in US France & Germany--







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[PT032AAD2], Technical Note, Thomas Alva Edison, May 14th, 1887

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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University


May 14, 1887