Nanocrystalline core for a current sensor, single and double-stage energy meters and current probes containing them

Abstract

A nanocrystallised tape-wound core without a localised airgap, consisting of a nanocrystalline material with the following atomic composition: [FeNi]100-x-y-z-a-β-γCuSiBNbM'M″, wherein a≦0.3, 0.6≦x≦1.5, 10≦y≦17, 5≦z≦14, 2≦a≦6, β≦7, γ≦8, M′ is at least one of the elements V, Cr, Al and Zn, M″ is at least one of the elements C, Ge, P, Ga, Sb, In and Be, with a permeability μ of 200 to 4000, a saturation of more than 1T, an induction range, in which the permeability does not vary by more than 5%, of more than 0.9T, a remanent induction of less than 0.02T and a cut-off frequency higher than 1 MHz, such that μ varies by less than 1% when the core is aged for 100h at more than 100° C., μ varies by less than 5% when the core is coated, μ varies by less than 15% when the temperature is in the range of −25° C. and +60° C., and by less than 25% when the temperature is in the range of −40° C. and +120° C., and μ varies in a monotonic and substantially linear manner with a temperature of −40° C. to +120° C.