Discussion on “instruments and measurements,” at Pittsburg, Pa., May 8, 1905

One would infer from Mr. Nies´ paper that the polyphase meter is an inherently inaccurate instrument. A polyphase meter so constructed that there are no mutual electrical or magnetic influences between the two meter elements, should and does operate just as accurately as the single element of a single-phase meter. This independence of the two meter elements is made permissible by connecting them together mechanically instead of electrically and magnetically. A polyphase meter mechanically connected between the two elements (that is, with two complete meter elements respectively acting upon two discs fixed to the same shaft) is polyphase only in that it may be so connected with polyphase circuits as to measure accurately the power whether the circuits are balanced or unbalanced.