Soft magnetic FeNi alloys for DC current sensors with high accuracy

This paper deals with the DC current sensor with closed loop and high accuracy, and describes the relationship between the latter and the core material magnetic properties. The coercive field H-c, which controls strongly the sensor accuracy, may fluctuate heavily with operating temperature and external stresses as shown in the cases of three different FeNi alloys. Non-coated Fe-80%Ni exhibit low H-c (< 1 A/m): this is kept (H-c ≤ 1.2 A/m) under strong external stresses (coating) when a low magnetostriction alloy is used. If coating-induced stresses are avoided, a FeNiCr alloy offers an interesting opportunity to get both good accuracy due to low H-c (≤ 2 A/m) and a cheaper solution. © 2004 Elsevier B.V. All rights reserved.