FREQUENCY CHARACTERISTICS OF ELECTRICAL MACHINES WITH A MESH WINDING DURING HEAT-AND-MOISTURE AGING

Authors

DOI:

https://doi.org/10.20535/1813-5420.1.2021.242164

Keywords:

high-frequency processes,, high-frequency, input impedance, electric machines with mush-wound windings, capacitance

Abstract

Operation of an electric drive with damages in power electric circuit of the motor stator results in asymmetry

of the motor phase current charge, increase of heating losses in certain phases, occurrence of variable components of electromagnetic torque and consumed power. An electric motor stator winding consists of a number of stator bars and overhang connections. Due to the complicated winding structure and the steel core, the attenuation and distortion of a pulse transmitted through the winding are complicated, and frequency-dependent. A low voltage impulse method and digital analysis techniques to determine the frequency characteristics of the winding are described. The frequency characteristics of electric motor stator windings are discussed in some detail. The analysis presented in this chapter could be applied to other rotating machines such as low voltage motors. An experiment of damping of electric motor wilding was conducted. Changes in frequency characteristics after the cycle are shown. In this article an analysis of the frequency characteristics of low-voltage electric machines with mush-wound windings, taking into account the processes of successive destruction of the insulation structure by the influence of heat-wet cycles. It is shown that the frequency characteristics can be generalized by the parameter of the state of isolation in the conditions of periodic monitoring of the quality of insulation during regulatory audits. It is proved that the frequency characteristics taken in idle and short-circuit modes have diagnostic features of the level of insulation destruction during humidification, which consist of shifting the characteristics of extremes into the region of lower frequencies, as well as reducing the area under the curve between the minimum and maximum extrema of the characteristic.

References

Investigation of the possibility of continuous insulation control of existing electrical installations without

their decommissioning // Proceedings of the Lugansk branch of the International Academy of Informatization. No1

(10) 2005 art. 87-90

V. Tarasyuk - Control and testing of insulation of windings of traction engines of electric trains during

repair // Proceedings of the Vernadsky Scientific Library in 2012.

В.А. Чернышев, Е.В. Зенова, В.А. Chernov et al. - Generalized polarization index as a parameter for

monitoring the state of insulating gaps of power transformers. // Proceedings of the IV International Conference

"Power Transformers and Diagnostic Systems". - 2009. - 653 p.

Jose Luis Oslinger, Luis Carlos Castro, "Correlation between capacitance and dissipation factor used for

assessment of stator insulation", Intern'l Journal of Electrical Engg., Vol. -6, no. 3, 2012.

Bakuradze LN, etc. Determination of the modes of the accelerated tests on safety of electroinsulating

designs of electric cars of small power. Electric machines, vol. II, 1978.

Published

2021-10-11

Issue

Section

MONITORING, DIAGNOSTICS AND MANAGEMENT BY ENERGY PROCESSES AND EQUIPMENT