Technikatörténeti szemle 9. (1977)

A MÉRÉS ÉS A MÉRTÉK AZ EMBERI MŰVELŐDÉSBEN című konferencián Budapesten 1976. április 27–30-án elhangzott előadások I. rész - Debreczeny Á.–Vajda P.: A Bláthy-féle fogyasztásmérő, az áramfogyasztás gyakorlati mérőmódszerei

Independent of the invention by Ferraris (16), the first induction-type meter (ampere-hour meter) was devised in 1886 by Francois Borel, a Swiss electrician (17). A major advance was made in 1888 by the Westinghouse meter of the American Oliver B. Shallenberg (18) — although the problem was not solved definitively. Like the Edison meter, the Shallenberger meter measured current and not electric energy. In a constant-voltage circuit with a noninductive (lighting) load, the energy consumed is proportional to the current. No appreciable error results from measuring the current alone. By today's standards, its accuracy could not have been very good; it was not provided with friction compensation; furthermore, its torque moment (proportional to the square of current) was too low at low loads. The first induction type alternating-current watt-hour meter, an instrument measuring the amount of work, was marketed in 1889 by the Ganz Factory, along patents by Otto Titus Bláthy (19) BLÁTHY'S A. C. Meter Patents Application Acceptance Country Date Date Nos. 1. Austria—Hungary 2. USA 3. Germany 4. Belgium 5. Great-Britain 6. Switzerland 7. France 8. Italy 1889. Aug. 1889. Sep. 1889. Sep. 1889. Sep. 1889. Sep. 1890. Jan. 1889. 1889. 1889. Oct. 1889. Oct. 13207—

XXIV—268 44023—40—45 USA Pat. 423210 DRP 52793 87942 14991/1889. 1534 1. Austria—Hungary 2. USA 3. Germany 4. Belgium 5. Great-Britain 6. Switzerland 7. France 8. Italy 1889. Sep. 1889. Oct. 1889. Oct. 1890. Feb. 1889. Dec. 1889. Dec. 201095 RGv. XIII 26256 RAv. LII 32 Blathy recognized that the Ferraris principle can be applied in the construction of an energy measuring device. In the original Ferraris motor, one of the two electro-magnets located along the circumference of the copper disc (acting as rotor), was connected in series with the load; the other electro-magnet was excited by a voltage derived from the power line in a parallel arrangement. The magnetic field of the magnet excited by the load current was in phase with the current flowing through the coil; the magnetic field of the magnet excited by the mains voltage was shifted in phase to a considerable extent (to nearly 90°) relative to the mains voltage because the exciter coil necessarily had a large number of turns and, hence, a high self-inductance. As a result of an interaction between the currents induced in the disc and the magnetic fields, a torque