Improvements in or relating to power factor measuring instruments

393,589. Power-factor measurements. ELLIOTT BROS. (LONDON), Ltd., Century Works, Lewisham, London, and SHOTTER, G. F., 14, The Ridgeway, Friern Barnet, Middlesex. Dec. 4, 1931, No. 33641. [Class 37.] A power factor meter has a series winding in the field of which move two coils connected to a pointer, one coil being connected across the supply and the other fed with a current displaced 90 degrees from that of the voltage coil, and means for varying the current in the two coils to give zero deflection. The series coil 4 is wound in two portions on projecting poles 2, 3, the coils 8, 9 embracing a fixed core-piece 7. The ends of each coil 8, 9 are connected to opposite ends of a potentiometer resistance 13 and to its slider 19, one of the coils being connected through a resistance 18 and the other through a condenser 21 or reactance. A reversing switch 20 is located in the circuit of coil 9. The resistance 13 is connected across the supply in series with a zero fine-adjusting resistance 16 and a current limiting resistance 17. The resistance 17 may be replaced by a reactance or condenser to reduce the voltage applied to the potentiometer. Each of the coils 8, 9 may be connected to separate potentiometers. The components are carried on the underside of a panel mounted in a casing, the position of the slider after the zero balance being a measure of the power factor.