GB632334A - Improvements in or relating to alternating current measuring instruments - Google Patents

Abstract

632,334. Power meters ; energy meters. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. June 26, 1947, No. 16901. Convention date, Sept. 17, 1941. [Class 37] In an induction type power or energy meter the inductance of the quadrature loop or other phase correcting device is adjustable to effect the required calibration or correction. The invention is described in relation to a watthour meter, Fig. 1 (not shown), whose quadrature loop 13 is embraced on one of its sides, as shown in Fig. 2, by a U-shaped block 14, Fig. 3, of magnetic material and calibration is effected by moving in or out as required a screw 16 in the slot 15. The screw 16 or block 14 or both, may be of material which possesses a negative temperature coefficient of permeability. In a modification, Fig. 4, the loop 13A is enlarged to include side apertures into which extend projections 9A, 10A integral with the core 1. The lag plate 13A in this case acts to lag the current flux flowing through 9A, 10A as well as the voltage flux flowing in the tip of the voltage pole 2. In Fig. 4 the phase correction is obtained by movement of a rod 24 rigidly secured to or in threaded engagement with a screw 22 within the bore 17A of the block 14A which may, as shown, abut the voltage pole 2.