STUDY OF THE CAPACITIVE SENSOR OF THE AIR GAP IN THE HYDROGENERATOR WITH PARALLEL COPLANAR ELECTRODES

Abstract

The paper describes the design, circuit and technological features of a capacitive sensor of the air gap (AG) between the bore of the stator core and the rotor poles in a capsule hydrogenerator, formed by a system of strip parallel coplanar electrodes. The system contains high-potential, low-potential and grounded electrodes. The change in electrical capacitance between the system of high-potential electrodes and low-potential electrode systems functionally depends on the change in the distance between the common plane of the sensor electrodes at the rotor poles, which is the value of the air gap. A method for experimentally determining the sensor conversion function is outlined. The equipment and measuring instruments used described. The research methodology for simulating changes in AG involves the use of a special device for parallel plane movement of a flat-grounded plate, which imitates the surface of a rotor pole in a machine. The plate moves along the device carriage relative to the common surface of the sensor electrodes, which fixed on the device. A micrometer head carries out the task of movement and its registration. Tabular and graphical data illustrating the experimentally determined transformation function obtained. A comparison of the experimental results with the theoretical ones confirmed the correctness of the proposed principles for constructing the sensor. The use of a sensor makes it possible to increase the accuracy of measuring AG in hydrogenerator, which will ultimately improve the assessment of the current technical condition of the machine.