BASICS OF PREVENTIVE MAINTENANCE OF ELECTRIC MACHINES BY VIBRATION

Аннотация

This article analyzes the basics of preventive maintenance of electrical machines for vibration in the automotive industry. In particular, it examines the sources and causes of vibration, types of vibration, vibration activity and noise, and the causes of their occurrence. It analyzes and proposes methods for solving problems of ensuring noiseless and reliable operation of electrical machines depending on their type, which directly affects the resource of electrical machines, production profitability, downtime of production machines, and equipment performance. Key words:noise, vibration, plain bearings, rollingbearings, rotor Introduction. The basis of modern production is electric machines and the issues of ensuring their reliable operation are significant for any enterprise. This applies to the automotive industry to a particular extent, since a stop of even less than one minute for a modern car plant with a production capacity of 200-250 thousand cars per year entails losses of at least 25 thousand US dollars. Therefore, the issues of technical maintenance of electric machines with an estimated determination of their performance are very relevant, and the study of the factors determining the choice of methods and parameters of measured quantities is also of great scientificand practical interest. Themain measurableparameters for preventive maintenance ofelectrical machines can be: Fig 1.measurableparameters for preventive maintenance ofelectrical machines The most common and easy to implement are measurements of noise and vibration indicators. The correct choice of measurement methods and tools depends on the nature of the occurrence of noise and vibration and therefore it is necessary to conduct a study of the causes of https://ijmri.de/index.php/jmsi volume 4,issue5,2025 317 theiroccurrence and manifestation inthe operation ofan electricmachine. An electric machine is a complex combination of interconnected oscillatory systems with several sources of disturbing forces [1]. The sources of disturbances inherent in electrical machines can be divided into three types: mechanical, magnetic, and aerodynamic. Mechanical sources of vibrations are caused by thedesign and technological features of theproduction ofcertain types of machines. Rotor imbalance occurs due to the discrepancy between its main central axis of inertia and the axis of rotation. When an unbalanced rotor rotates, its supports are subject to dynamic forces, the components of which, lying in any plane passing through the axis of rotation, change with the angular velocity of the rotor. The reasons for the appearance of rotor imbalance can be very different [3]. Reducing the level of disturbances can be achieved by reducing the residual imbalance. However, it is impossible tocompletely balance the rotor. Moreover, for some types of machines, uncontrolled imbalance may occur. In this case, special design measures are used. The most well-known of them are thefollowing: 1.elastic supportswith linear andnonlinear characteristics; 2.elastic-dampingand damping supports; 3.antivibrators [4]. Elastic elements, built in between the rotor and the machine body, allow to tune the rotor- body system from resonance modes and thus reduce the transfer of disturbing forces to the body and ultimately to the foundation. The design of elastic supports is diverse. Rings, plates, tapes, springs, etc. are used asan elasticelement. It should be noted that the use of elastic supports with a linear characteristic allows shifting the critical rotor speeds from the operating speed range without structural modification oftherotoritself, without changing its mass and the mass oftheentire machine. However, in this case, the range of operating speeds free from critical numbers is limited by the minimum permissible value of support rigidity. This circumstance turns out to be decisive for multi-mode machines, which have a large range of change in speed numbers. Unlike linear supports,nonlinear supports generally allowtheelimination ofcritical modes [4]. The use of elastic-damping and damper supports allows for tuning out critical modes and at the same time significantly limiting the level of rotor oscillation amplitudes when passing through the critical speed. A common disadvantage of elastic-damping and damper supports of liquid friction is the strong dependence of their properties on the viscosity of the damping liquid, which, in turn, is determined by the thermal conditions of the support. If the same liquid is used for damping and lubrication, which significantly simplifies the design, then it is necessary to thermostatically control theliquid suppliedtothedamper. The peculiarity of using dry friction dampers is that depending on the magnitude of the disturbing force and the angular velocity, the dry friction support is absolutely rigid (the damper is “closed”) or damping (the damper is “open”). This can be used to eliminate critical modes. https://ijmri.de/index.php/jmsi vo