What Is The Difference Between An Electric Eddy Current Sensor (resolver) And A Conventional Resolver

Electric Eddy Current Sensor Resovler

An electric eddy current sensor is a non-contact, high-linearity, and high-resolution measurement tool used to measure the distance between a metal conductor (the measured body) and the surface of the probe, either statically or dynamically. It operates based on the principle of the eddy current effect, which occurs when a block-shaped metal conductor is placed in a changing magnetic field or moves to cut magnetic lines of force in a magnetic field. This results in a swirling induction current within the conductor, known as the eddy current.

The sensor system consists of a preamplifier, an extension cable, and a probe coil. The high-frequency oscillating current in the preamplifier flows through the extension cable into the probe coil, generating an alternating magnetic field at the coil's head. When the metal body to be measured approaches this magnetic field, an induction current is generated on the metal surface. This eddy current field also produces an alternating magnetic field in the opposite direction to the head coil, causing changes in the amplitude and phase of the high-frequency current in the head coil (the effective impedance of the coil). These changes are related to parameters such as the permeability and conductivity of the metal body, the geometric shape and size of the coil, the current frequency, and the distance between the head coil and the metal conductor surface.

Electric eddy current sensors are characterized by their long-term reliability, high sensitivity, strong anti-interference ability, non-contact measurement, fast response speed, and immunity to media such as oil and water. They are widely used in industries such as power, petroleum, chemicals, and metallurgy for online monitoring and fault diagnosis of large rotating machinery, such as turbines, generators, compressors, and gearboxes.

Conventional Resolver

In contrast, a conventional resolver is a device used to resolve or convert one form of measurement into another, typically in the context of angular position or speed measurement in electrical machines. It operates on the principle of electromagnetic induction and typically consists of a rotor and a stator, with the rotor carrying a set of windings that move relative to the stator windings. As the rotor rotates, it induces a voltage in the stator windings that can be used to determine the rotor's angular position or speed.

The main difference between an electric eddy current sensor and a conventional resolver lies in their application and measurement principles. An electric eddy current sensor is designed for non-contact measurement of displacement, vibration, and other parameters of metal objects, while a conventional resolver is used for angular position or speed measurement in electrical machines.

In summary, while both devices utilize electromagnetic principles, their design, application, and measurement capabilities differ significantly.