Patent GB-190125403-A (GB)
Title: Improved Electric Energy Meter.
Inventor: THOMPSON WILLIAM PHILLIPS
Filed: 1901-12-12
Granted: 1902-12-12
Abstract: 25,403. Thompson, W. P., [Decombe, L.]. Dec. 12. Energy meters.-The movable part of an astatic electrodynamometer, carrying any kind of current, is oscillated electromagnetically at a rate proportional to the power passing, and the oscillations are counted. The pressure coils 2 are supported by transverse pivots 5 in a freely-movable vertical frame F, so that the axes of the coils may stand vertical, or may be turned to any angle from the vertical by the magnetic action of stationary main current coils 1. The coils 2 carry rings 7, geared to wheels of half their diameter, which carry weighted arms opposing the turning of the coil axes from the vertical ; the two rings 7 are geared together by a chain 6 or otherwise, to move alike. The coils 2 are balanced so that, in all positions, their moments of inertia about the vertical axis of the frame F are constant. The frame F has a horizontal arm carrying metal segments in contact with one or two stationary connecting-rollers 16, supported on springs 18 ; the segments and roller are arranged to open the pressure circuit through the coils 2 for a short time at the middle of each swing of the frame F. The pressure circuit includes a solenoid 29, acting on an armature lever 27 in opposition to a spring, so that, when the pressure circuit is opened, the lever 27 closes an auxiliary circuit at 38. The auxiliary circuit is connected through a two-way tumbling switch 21 to either of two stationary solenoids 15, which act oppositely on an armature 25, carried by a second arm of the frame F, to give a momentary impulse to the latter at the middle of each swing. The coils 1, 2 co-operate to return the frame F to the middle position. The two-way switch 21 is turned by a projection 22 on the second arm of the frame F. The currents thus supplied to the solenoids 15 also operate any suitable registering-gearing. A spring switch 36 is operated by an electromagnet 30, connected in parallel to a part of a main, to close the pressure circuit of the meter only when the main conveys current. The switch 36 is placed so as to give a starting-impulse to the part 22 of the frame F, when the current is first supplied. The auxiliary circuit, containing the two-way switch 21 and the solenoids 15, may be in parallel to a part of one main, or connected between the mains. Or the auxiliary circuit and the starting-magnet 30 may receive current from a thermopile heated by a part of the main. Or they may connect two opposite junctions in a balanced quadrilateral arrangement of resistances, the other junctions of which are connected to a galvanic battery ; one resistance of the quadrilateral is connected in parallel to a part of a main, and is heated by passage of current therein, so that current from the battery is caused to flow in the bridging- circuit. The iron armatures 25, 36 may be replaced by coils supplied from a main, the frame F being provided with a metal plate arranged to cut the magnetic field of the main coils 1, and so act as an eddy current brake, The main coils 1 consist of strip wound on edge, or wound spirally with an insulating- layer.