Abstract: Current testing/measuring apparatus 10 comprises a flexible member 12 having a first end 14 and a second end 16. In use, the flexible member 12 is arranged to locate around a conductor 11 carrying a current to be measured. In particular, the current measuring apparatus 10 comprises a Rogowski coil. The ends of the flexible member 12 are coupled together in use but a gap is created between the ends. This distance can generate errors in the current measurement and the present invention provides compensation means 28 in the form of a compensation windings. The compensation windings comprise a planar spiral conductor provided on a printed circuit board to compensate for the separation distance between the first end and the second end.

Abstract: The current measurement apparatus comprises a Rogowski coil 20 comprising a wire or conductor which forms a coil 22 and returns through the coil 22 as a central conductor. The coil 22 and the central conductor are formed from a single conductor or wire and, therefore, no electrical join (for example, a solder join or crimp) is required at the end of the Rogowski coil. The wire 28 used to form the coil 22 and the central conductor 24 is insulated prior to forming the Rogowski coil. The insulated coating 30 provides better insulation between individual coils and also helps to provide a more even spacing between the coils.

Abstract: A magnetic field sensor comprises a magnetic field sensing cell and a magnetic shield comprising at least two parts separated by an air-gap and surrounding the magnetic field sensing cell positioned in a cavity of the magnetic shield.

Abstract: An apparatus for deriving data concerning the electro-chemical characteristics of a plurality of individual electro-chemical cells or corrosion processes is disclosed. In one aspect, the apparatus includes means for temporarily applying across a cell or a process a controlled multi-frequency electrical signal; means for detecting returned data resultant from said application, and means for utilizing the returned data with to resolve the data into at least three of its electro-chemical constituents, including a series metallic resistance, an electro-chemical resistance, and a double-layer capacitance.

Abstract: Current testing/measuring apparatus 10 comprises a flexible member 12 having a first end 14 and a second end 16. In use, the flexible member 12 is arranged to locate around a conductor 11 carrying a current to be measured. In particular, the current measuring apparatus 10 comprises a Rogowski coil. The ends of the flexible member 12 are coupled together in use but a gap is created between the ends. This distance can generate errors in the current measurement and the present invention provides compensation means 28 in the form of a compensation windings. The compensation windings comprise a planar spiral conductor provided on a printed circuit board to compensate for the separation distance between the first end and the second end.

Abstract: A current sensor comprises an outer shielding means (4), a toroidal inner core and inner shield means (1). A combined driving and sensing winding (3) is wound around the inner core. First and second ends of the winding (3) are connectable to a sensor head. The inner shield means (1) has a gap (1A) formed in it.

Abstract: The current measurement apparatus comprises a Rogowski coil 20 comprising a wire or conductor which forms a coil 22 and returns through the coil 22 as a central conductor. The coil 22 and the central conductor are formed from a single conductor or wire and, therefore, no electrical join (for example, a solder join or crimp) is required at the end of the Rogowski coil. The wire 28 used to form the coil 22 and the central conductor 24 is insulated prior to forming the Rogowski coil. The insulated coating 30 provides better insulation between individual coils and also helps to provide a more even spacing between the coils.

Abstract: An apparatus for deriving data concerning the electro-chemical characteristics of a plurality of individual electro-chemical cells or corrosion processes is disclosed. In one aspect, the apparatus includes means for temporarily applying across a cell or a process a controlled multi-frequency electrical signal; means for detecting returned data resultant from said application, and means for utilizing the returned data with to resolve the data into at least three of its electro-chemical constituents, including a series metallic resistance, an electro-chemical resistance, and a double-layer capacitance.

Abstract: The invention concerns magnetic sensors and, particularly, a magnetic sensor arrangement for use in an electrical measuring device. In the device, magnetic sensors are provided within recesses formed in the arms of the device. The recesses are typically formed within laminations and act so as to shield the magnetic sensors from interference, whilst enabling them to detect a magnetic field of an electrical conductor placed between the two arms.

Abstract: An electrical measuring device has measuring elements for fitting around an electrical conductor, so that a property associated with the conductor can be measured. The device has a display unit 13 which can be used to display information relating to the property being monitored. The measuring elements for fitting the device around the conductor include a pair of jaws 16, 17, each mounted on a body member 12 for movement with respect to the body member, so that the jaws can move towards and away from one another. A plurality of connection terminals 25, 26, 27 and 28 are provided, together with a selection mechanism arranged such that, when at least one terminal is accessible, at least one other terminal is inaccessible. The device has an output terminal 29, from which an output signal can be derived, with isolation elements 35, 36 to isolate the output terminal from other components of the device, to avoid or reduce the risk that high voltages will be transmitted to the output terminal.