Magnetic field components are measured at multiple longitudinal positions and used to calculate estimated longitudinal position and length of a transversely localized electric current segment flowing across a gap between conductive bodies. The apparatus can be used with a remelting furnace. The electrode and ingot act as the conductive bodies, and arcs, discharges, or slag currents are the current segments spanning the gap. Actuators for movable sensors can be coupled to the sensors in a servomechanism arrangement to move the sensors along with the moving gap. An actuator for moving one of the conductive bodies can be coupled to sensors in a servomechanism arrangement to maintain the gap distance within a selected range as the gap moves.

Magnetic field components are measured at multiple longitudinal positions and used to calculate estimated longitudinal position and length of a transversely localized electric current segment flowing across a gap between conductive bodies. The apparatus can be used with a remelting furnace. The electrode and ingot act as the conductive bodies, and arcs, discharges, or slag currents are the current segments spanning the gap. Actuators for movable sensors can be coupled to the sensors in a servomechanism arrangement to move the sensors along with the moving gap. An actuator for moving one of the conductive bodies can be coupled to sensors in a servomechanism arrangement to maintain the gap distance within a selected range as the gap moves.

A magnetic field detecting device which comprises a magnetic impedance sensor including a magnetic impedance element 1 in which a pulse electrical current or a high frequency electrical current is applied from an oscillator 2 to an amorphous wire 10 and an alternate current or AC damped oscillation voltage, which is induced in a detecting coil 11 wound around the amorphous wire 10 and has a magnitude corresponding to an external magnetic field, is output, and an arbitrary magnetic field is applied to the amorphous wire by means of the magnetic field generated on the detecting coil 11 energized by connecting the detecting coil 11 to a voltage source or to a current source E through an impedance network 3 comprising of a resistor R or a coil L or a condenser C or comprising a combination of the resistor R, the coil L, and the condenser C.

A magnetic field measurement device capable of accurate measurement of a magnetic field even after a sensitivity of an MI sensor varies is provided. A magnetic field measurement device (1) includes an MI sensor (2) and a sensitivity calculation means (3). The MI sensor (2) includes a magneto-sensitive body (20), a detection coil (21) and a magnetic field generation coil (22) that generates a magnetic field upon energization. The sensitivity calculation means (3) varies a current flowing in the magnetic field generation coil (22) in a state where an outside-sensor magnetic field H.sub.O acting on the magneto-sensitive body (20) from outside the MI sensor (2) is constant. Consequently, the magnetic field acting on the magneto-sensitive body (20) is varied to calculate a sensitivity a by dividing a variation in an output voltage of the detection coil (21) by a variation in the magnetic field acting on the magneto-sensitive body (20).

In a magnetic sensor using sensitive circuits sensing magnetic fields by the magnetic impedance effect, a sensitivity-to-noise ratio is improved. A magnetic sensor 10 includes: a sensitive circuit 12A including sensitive parts sensing magnetic fields by magnetic impedance effect; and a sensitive circuit 12B including sensitive parts sensing magnetic fields by magnetic impedance effect, wherein at least a part of current paths of the sensitive circuit 12A and at least a part of current paths of the sensitive circuit 12B overlap in a plan view, and one end portion of the sensitive circuit 12A and one end portion of the sensitive circuit 12B are electrically connected.

A magnetic sensor 10 includes: a non-magnetic substrate 11; a sensitive circuit 12 provided on a surface of the substrate 11 and including a sensitive part 121 sensing a magnetic field by a magnetic impedance effect; a terminal part 13a and a terminal part 13b connected to respective both end portions of the sensitive circuit 12; and a conductive returning member with one end portion being connected to the terminal part 13a, the returning member returning back toward the terminal part 13b.

A magnetic sensor 1 includes: a non-magnetic substrate 10; and a sensitive element 30 disposed on the substrate 10. The sensitive element 30 has a longitudinal direction and a transverse direction and has a uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction. The sensitive element 30 is configured to sense a magnetic field by a magnetic impedance effect. The sensitive element 30 includes a soft magnetic material layer 101 made of an amorphous alloy based on Co and having a saturation magnetization of greater than or equal to 300 emu/cc and less than or equal to 650 emu/cc.

Sensors measure magnetic field components, and the measured fields are used to calculate and estimated transverse position of a longitudinal electric current flowing as an electric discharge across a discharge gap. Based on the estimated position, and according to a selected transverse trajectory or distribution of the estimated discharge position, magnetic fields are applied transversely across the discharge gap so as to control or alter the estimated discharge position. Inventive apparatus and methods can be employed, inter alia, during operation of a vacuum arc furnace.

Sensors measure magnetic field components, and the measured fields are used to calculate and estimated transverse position of a longitudinal electric current flowing as an electric discharge across a discharge gap. Based on the estimated position, and according to a selected transverse trajectory or distribution of the estimated discharge position, magnetic fields are applied transversely across the discharge gap so as to control or alter the estimated discharge position. Inventive apparatus and methods can be employed, inter alia, during operation of a vacuum arc furnace.

A magnetic sensor arrangement for determining information indicative of characteristics of a mechanical component has a first magnetic sensor to sense a signal associated with a periodic changing magnetic field generated by relative movement of the mechanical component and the magnetic sensor arrangement, a second magnetic sensor to sense that signal, wherein the first sensor is arranged a fixed distance from the second sensor, and a determination unit coupled to the first and second sensors to receive output signals of the first and second sensors. The output signal of the first sensor is phase-shifted to the output signal of the second sensor, to compare the output signals for determining the absolute phase of the signal associated with the periodic changing magnetic field, and to determine information indicative of characteristics of the mechanical component based on the determined absolute phase of the signal associated with the periodic changing magnetic field.