VIBRATION DIAGNOSTICS SYSTEM FOR ELECTRIC MOTOR WITH ACTIVE ULTRASONIC SENSING
At present, part of the fixed assets of electric grid infrastructure is becoming obsolete in the Russian Federation. It leads to an inevitable decrease of operational reliability of single electrical equipment and power-supply systems as a whole. At the same time the requirement to the reliability for most electrotechnical complexes is the main one. As a result, diagnostics is the most important process in electrical equipment’s operation. Diagnostics is based on measurements, control and analysis of a large number of equipment’s characteristics and parameters. One of the important components of diagnostics is vibration control, as it allows detecting a large number of mechanical defects and defects in electrical or magnetic parts of electrical equipment. Vibration control, as a means of malfunctions diagnosis and ensuring the stable operation of electrical equipment, is most often carried out by contact sensors. The paper describes the experimentally tested vibration diagnostics system for an electric motor, which is based on remote ultrasonic measurements together with contact measurements. It is shown that remote measurements allow controlling moving elements and having more capabilities than contact ones. A significant difference between vibration signals obtained by different methods was found: using traditional contact sensors installed on the engine body and using active ultrasonic sensing of rotating elements. A comparative analysis of information obtained from contact and noncontact sensors is proposed for the diagnostics of electrical equipment. The analysis was carried out both in starting and steady state operation modes of the electric motor. The joint use of contact and remote measurements significantly increases the informative value and data reliability of technical condition forecasts.