Improvements in electrical measuring and/or signalling systems

Abstract

Abstract 450,864. Frequency measurements. AUTOMATIC ELECTRIC CO., Ltd., Strowger Works, Liverpool, and RAYNER, T. R., 2, Stretton Avenue, Wallasey, Cheshire. Jan. 24, 1935, No. 2835. [Class 37] [See also Group XXXVIII] Frequency measurements are effected by comparing the output of a synchronous motor generator driven at a speed corresponding to the frequency to be measured with the output of a second motor generator run at a known speed. As shown, the current of the frequency to be measured operates a synchronous motor generator S1, DI through an amplifier demodulator D, the output of the generator D1 being connected in opposition through a central-zero instrument G to the output of a motor generator S2, D2 driven at known speed by an oscillator under the control of a tuning-fork TF. Several measurements may be effected simultaneously over the same circuit by utilizing carrier currents of different frequencies modulated by the currents to be measured. When the system is arranged to give a number of indications a single standard speed motor drives a number of generators or a number of separate motor generators are provided.

Inventors

No inventors recorded.

Bibliographic Details