Eddy current sensor
First Claim
1. Eddy current sensor with an evaluation circuit, with at least one measuring coil, and with at least one compensat ing coil, wherein the measuring coil a nd the compensating coil can be supplied with alternating currenr, and the compensating coil is arranged in direct vicinity of the measuring coil, so that the electromagnetic fields of the compensating coil and measuring coil are orthogonal to each other, wherein the measuring coil has an annular form and the compensating coil is wound around the measuring coil in the form of a torus, so that th e compensating coil is in thermal c ontact with the measu ring coil.
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Accused Products
Abstract
An eddy current sensor (1) has at least one measuring coil (2) that can be supplied with an alternating current, and an evaluation circuit (3). The eddy current sensor allows the temperature influences on the impedance of the measuring coil to be reliably compensated with a simple design and an evaluation circuit. For this purpose, the eddy current sensor has a compensating coil (4) which can also be supplied with an alternating current and which is arranged closely to the measuring coil, i.e. in thermal contact therewith, in such a way that the electric fields of compensating coil (4) and measuring coil (2) are orthogonal to each other. More particularly, the measuring coil (2) is in an annular form and the compensating coil (4) is wound around the measuring coil in the form of a torus.
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Citations
17 Claims
- 1. Eddy current sensor with an evaluation circuit, with at least one measuring coil, and with at least one compensat ing coil, wherein the measuring coil a nd the compensating coil can be supplied with alternating currenr, and the compensating coil is arranged in direct vicinity of the measuring coil, so that the electromagnetic fields of the compensating coil and measuring coil are orthogonal to each other, wherein the measuring coil has an annular form and the compensating coil is wound around the measuring coil in the form of a torus, so that th e compensating coil is in thermal c ontact with the measu ring coil.
Specification