Abstract
It is shown that the derivative of the work or its corresponding mechanical energy is thermal power, which is called active in electrical engineering. This power is pulsating, but of constant signs, since the heat flux during mechanical vibrations is irreversible. The time derivative of kinetic energy is alternating in sign; therefore, its equivalents in electrical engineering are called reactive. Most drives of machines and mechanisms are electromechanical; therefore, in accordance with the energy conservation law, during vibrations of massive workpieces, parts, assemblies and other units reactive mechanical power is transformed into reactive electric power of the supply network, substantially worsening the quality of current and causing noticeable losses in wires during its circulation. In this regard, the task of correct accounting of both active and reactive mechanical power for energy-saving purposes, as well as power design calculations is relevant. The objective of the paper is to establish the relationship between active, reactive and full power during mechanical vibrations. Reactive (inertial) power is a purely imaginary value. Active (thermal) power at any nature of movement, for example, developed by the sliding friction force, is a real value. Active and reactive mechanical powers, being conditionally “orthogonal”, do not add up. For full power, a law similar to the Pythagorean Theorem is valid (just like in electrical engineering). Inert and elastic reactance characterizes the properties of massive and elastic bodies to resist the drive, which forces them to oscillate. Due to the special features of the operation of vibrating machines, inert reactance is one of their key parameters.
Keywords
Inert, elastic reactance, drive, active, reactive, full power.
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