SU1737634A1 - Method of checking of parameters of air gap of electric machine - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to expand the scope of application of the method to control the absolute size of the air gap. The method of controlling the parameters of the air gap of an electric machine is that the electric machine is rotated, the vibrations on its body are changed, and the vibrating signal is filtered. The modulation factor of the vibration signal QC is measured at a frequency equal to the frequency of rotation of the core co0. The eccentricity of the core ei and the critical frequency of rotation o) «p are preliminarily changed, and the size of the air gap is determined by the formula b 2ei / {Kk (ucr / d o) 2 -. 2 Il.

Description

(L

WITH

The invention relates to mechanical engineering, in particular, to the control of the technical condition of an electric machine.

For this, the air gap is calculated from the magnitude of the eccentricity of the core, the modulation factor of the vibration signal, due to the frequency of rotation of the core and the critical frequency of rotation of the core.

The invention relates to mechanical engineering and can be used primarily to control the technical condition of the air gap in the magnetic system of an electrical machine.

The purpose of the invention is to expand the scope of application of the method by controlling the absolute size of the air gap in the magnetic system of an electric machine.

Figure 1 shows a general scheme for measuring the vibration spectrum of an electric motor; figure 2 - spectrogram modulated by the amplitude of the vibration signal

at the tooth frequency, by the vibration signal at the frequency of rotation of the core.

The vibrations at the tooth frequencies of an electric machine are associated with pulsations of magnetic forces in the air gap between the core and the stator poles. Elastic deflection of the core during rotation causes a cyclical change in the gap with the frequency of rotation. The driving force at the tooth frequency is the modulated rotation frequency, and the vibration of the mechanism at this frequency is also modulated.

Then the size of the air gap between the core and the stator is determined as

 Kk () o) 2-1. (one)

where ei is the mass eccentricity of the core,

Kk is the modulation factor of the vibration signal, due to the frequency o) o of rotation of the core,

Vj

CO VI

about

with

four

WKP - critical speed of rotation of the core.

The method is implemented as follows using the device (Fig. 2). The device contains an electric motor 1 mounted on vibration isolators 2. The motor has a vibration sensor 3 connected to the recorder 8 via a series-connected PU 4 preamplifier, a PF 5 band-pass filter, a D 6 detector, and a ULF low frequency amplifier. with fairly simple software. The vibration sensor 3 registers the vibration spectrum of the operating electric motor 1. The signal is amplified by the PU, then the RF component of the signal at the tine frequency is detected, which is detected D. After the detection, the vibration signal is amplified by the ULF and fed to the input of the computer. At the computer input, the vibration signal contains a constant component Uo (Fig. 2) and a variable component having in practice several frequencies. The computer programmatically selects a signal with a rotational speed of a) o and determines the modulation coefficient, K Uo / iU. The values of ei are determined by any known method, and a) Kp during the acceleration of the core during the start of the mechanism.

According to the obtained results and expression (1), the size of the air gap in the magnetic system of the electrical machine is determined.

The use of the invention allows to increase the accuracy and reliability of technical control by determining the current value of the air gap of the magnetic system

Claims (1)

machine during its operation. The invention of the method of monitoring the parameters of the air gap of an electric machine, which consists in that the electric machine is driven rotate, measure vibrations on its body, filter the vibrosignal, measure the modulation factor of the vibratory signal and use this value to control the air gap parameters, in order to expand the field of application of the method by controlling the absolute size of the air gap, pre-eccentricity of the core ei and the critical frequency of rotation of the core (Odr its acceleration time, and the modulation coefficient Kk is measured at a frequency equal to the core rotation frequency o), and the air gap is determined by the formula d-2ei /: kk (u Kp / eOo). Phage.1 2