GB508046A - Improvements in or relating to the measurement of magnetic fields - Google Patents

Abstract

508,046. Magnetic measurements. SIEMENS APPARATE UND MASCHINEN GES. Dec. 24, 1937, Nos. 35806 and 35807. Convention dates, Dec. 24, 1936 and March 3, 1937. [Class 37] Measurements of a magnetic field are made by means of a wound core of high permeability material located in the field and supplied with an auxiliary alternating, or periodically variable continuous-current that produces a flux employed for measurement purposes, the desired quantities being obtained by' measuring the effective impedance or impedance changes produced as the field under investigation changes, or by measuring the voltages set up by impedance variations. Auxiliary windings may be provided on the core and these may be polarized. In one arrangement, Fig. 3, the core is fed with alternating-current in winding 2 which is connected to a rectifier supplying a polarizing winding 6. In Fig. 8 the core 101 has end-pieces of larger section and is fed with continuous-current through a mechanical vibrator 105. Fig. 12 shows two wound core members 101; 102 arranged in bridge fashion with resistors 112, 113, the source of current being A.C. or interrupted D.C. The instrument 114 can be a meter, relay or amplifier. Differential instruments are also employed in other modifications. Capacitances can be arranged in the auxiliary circuit for producing oscillation currents. In Fig. 10, a further source of. continuous-current 108 is provided for compensating the closed circuit current when the open circuit flux is zero. In Fig. 15, the core 101 has two restricted parts on which primary and secondary windings 102, 119 are located.