Current detector and current measuring apparatus including such detector with temperature compensation

摘要

A current sensing device and a residual current detection device are described having a temperature compensation capability so that residual current can be directly measured to a high degree of precision in the background of a high load current. The residual current device comprises a plurality of resistive shunts (14) for connection in respective ones of a plurality of lines through which current can flow to and from a load, and detector means (15) sensitive to the voltage developed across each of the shunts to detect any imbalance between the currents flowing through the shunts. The temperature compensation means (15h) is provided for facilitating compensation for fluctuations in shunt resistance with variations in temperature. The current sensor comprises a rigid metallic link member having two end portions (13) of conductive material and an intermediate portion (14) interconnecting the end portions. The intermediate portion is formed of a resistive material, and an integrated circuit analog to digital converter (15) is mounted on said link member. The converter has analog input terminals connected to respective ones of said two end portions and digital output terminals for connection to a processing apparatus. A temperature sensor (15h) is provided on or within said intermediate portion.