SU1089527A1 - Method of checking disbalance of electric motor rotor - Google Patents

Description

The invention relates to electric machines, mainly aviation ones, and can be used to control the imbalance of assembled electric motors during production and operation.

Methods are known for measuring unbalance based on an increase in the speed of rotation of an electric machine and fixing with its sensor the displacement axis of rotation of its rotor at the time of equality of the centrifugal force and weight of the rotor l).

A disadvantage of the known methods is the need to use sensors, as embedded ones, and the associated implementation complexity and limited scope.

The closest to the present invention is a method for controlling the rotor's balance of an electric motor mounted on a ball joint, based on the continuous measurement of the frequency of rotation of the rotor from. the process of smoothly increasing it, measuring the motor current, continuous extraction of a component from it with a frequency

D-dtosei. Qui2; (J-5-

where Z, is the number of bearing balls; D is the bearing diameter at the centers of the rolling elements; o is the diameter of the balls; cs6 - contact angle,

fixing the value of the rotor rotation frequency to, at which an abrupt decrease in the amplitude of the selected component occurs, and on the assessment of the imbalance from the condition of equality of the centrifugal force from the imbalance and the weight of the rotor 2j.

The disadvantage of this method is the low accuracy of determining the rotor speed, at which the moment of equality of the centrifugal force from the unbalance of the rotor and the weight of the rotor occurs.

The purpose of the invention is to improve the accuracy of the control.

The goal is to achieve: xqM, that according to the method of controlling the unbalance of the rotor of an electric motor mounted on ball bearings based on the continuous measurement of the rotational speed of the rotor W in the process of its smooth increase, measuring the current of the engine, continuously decoupling from it the frequency

D-c3coset

OJy iZU) 2D

the number of bearing balls with a diameter B along the centers of rolling bodies; ball diameter j contact angle.

fixing the value of the rotor rotation frequency about J at which the amplitude of the selected component abruptly decreases, and on the assessment of the imbalance. Due to the equality of the centrifugal force from the unbalance and the weight of the rotor, after increasing the rotor rotation frequency, it gradually decreases, while continuously guide

current ripple spectrum with frequency

T) + dcose6

so;

,

they fix the value of the frequency of rotation 5, the rotor Nj of Wj in a moment in a jump-like manner. reduction of the amplitude of the current component with the frequency Wu, and for estimating 1 and the unbalance magnitude, the rotational speed of the rotor is used as

0 average frequency cj, and t02

With increasing speeds. the rotor of an electric machine, the change of the rotor motion modes in ball bearings (from the rocking motion of the rotor to the running mode of all the balls) does not occur when the centrifugal force is exactly equal to the imbalance and weight of the rotor;

Q is the centrifugal force over the weight of the rotor, so the rotor's rotational speed will be somewhat overestimated.

and, - COP + BCO ,,

5 where o, is the frequency of rotation of the rotor, at which the change of the modes of movement of the rotor occurs during a gradual increase in its frequency of rotation; Up is the frequency of rotation of the rotor.

at which the centrifugal force from the unbalance is equal to the weight of the rotor,

ÑСО - methodical error of determining Up with increasing rotor speed.

This is due to the inertia of the mechanical system.

For the same reason, the change of the rotor motion modes in ball bearings with a gradual decrease

The rotational speed of the rotor does not occur with exact equality of the centrifugal force from the imbalance and the weight of the rotor, but with some difference, i.e. F P, where F is the centrifugal force from.

55 imbalances; P is the weight of the rotor.

Then the rotor speed measured in this case will be somewhat less than the desired one.

(2)

and, 01р-Д 2,

rotor speed,

in which the change of the rotor motion modes occurs during the smooth reduction of the first,

. i, CJ2 methodical error of determining tJp with decreasing rotor speed. Let us now find the average value of two rotor rotation frequencies measured with a gradual increase and decrease in the rotation frequency during the change of the rotor motion modes

- OASCO

C.S.R.1-, i.e. wed 2 .- f 2

Lee, -С02О)

4p.

Comparing relations (1) and 3, it can be seen that (Oj.p-iOpt со, - (Op, i.e., the average value of measured frequencies) is closer to the desired CJp value, corresponding to the equality of centrifugal force from imbalance and rotor weight, than measured in the prototype the value of the h-asttoty of rotation of the rotor G), with a gradual increase in the latter ..

The drawing shows the st) circuit diagram of a device that implements the proposed 1L method.

The device contains a pulsation sensor 1, a notch filter 2, two selective automatically tunable filters 3 and 4, a frequency meter 5 and. Registrar 6.

The pulsation sensor 1 is the motor itself, or rather its winding, for example, the root. Notch filter 2 is designed. to suppress the fundamental harmonic of the supply voltage of ac motors, and for dc motors, it is not needed. Selective automatically tunable filters 3 and 4 serve to isolate the motor current ripple from the spectrum, respectively, at a frequency that is a multiple of the rotor speed, and compared to the ball frequencies of CO and SOC, with increasing and decreasing, the rotor rotation frequency, respectively. Search and capture of informative components by selective filters is carried out by Bpy4Hsno and subsequent automatic reordering, the construction can be carried out by switching on, for example, the operation of the circuit (phase-locked loop). Frequency meter 5 is used to measure the frequency of the reverse component and output information to the recorder 6, which simultaneously records information about the frequency of the spectral component multiple of the rotor speed and the amplitude of the components with the frequency of rotation of the balls (and (Oz respectively with increasing and decreasing frequency of rotation rotor. It gives the opportunity

determine the rotor rotational frequencies (O, and iOj at the moments of a sharp decrease in the amplitudes of the spectral components with frequencies N (and and cjy, respectively.

In the implementation of the method, from the pulsation spectrum of the electric motor, the component is continuously injected with a frequency multiple of the rotor rotation CJ, and a component with the frequency of rotation of the balls

the process of smoothly increasing the frequency of rotation of the electric motor. The frequency of the component, a multiple of the rotation frequency of the rotor, is then measured, and information is simultaneously recorded

on the frequency of the spectral component of the multiple frequency of rotation of the rotor and on the amplitude of the component with the frequency of rotation of the balls. Fix the value of the frequency w, spectral

a component that is a multiple of the rotor rotation frequency at the moment of a sharp decrease in the amplitude of the spectral component with the frequency of rotation of the balls O.

 The current pulsation spectrum of an electric motor continuously separates a component with a frequency multiple of the rotational speed of the rotor O and a component with the frequency of rotation of the balls

In the process of smoothly improving the frequency of rotation of the motor, then the frequency of the component, which is a multiple of the frequency of rotation of the rotor, is measured.

At the same time, information about the frequency of the spectral component is recorded with a multiple of the rotation frequency of the rotor and the amplitude of the component with the frequency of rotation of the balls.

wki fix the value of the frequency O of the spectral component to a multiple of the rotor speed at the time of a sharp decrease in the amplitude of the spectral component with the frequency of rotation of the balls SOTS, the sought value

the rotor speeds U are determined by toT as the average value of the fixed frequencies O, and b), and the unbalance value is determined by the known formula.

Thus, the proposed technical solution makes it possible to increase the accuracy of controlling the unbalance of the rotor of an electric motor without using a special sensor by more accurately determining the rotation frequency of the rotor, at which the centrifugal force is equal to the unbalance and the weight of the rotor.

. Improving the accuracy of the imbalance control provides a more accurate determination of the dynamic loads in ball bearings and thus makes it possible to more accurately predict

JHX durability, which, ultimately, 5 allows to increase the periolicity of the control. In turn, the increase in the frequency of control 1089527 provides a reduction in the cost of maintenance of various electric motors.

Claims (1)

METHOD FOR CONTROL OF THE MOTOR MOTOR ROTOR IMBALANCE mounted on ball bearings, based on continuous measurement of the rotor speed ω during its smooth increase, measurement of the motor current, continuous separation of a component from it, with a frequency D- <Jco5 <£. ^ 11) = ζ, ω 20- ⁵ number of bearing balls with a diameter on centers where P 2. rolling elements; from! - the diameter of the ball moreover, in order to increase the accuracy of control, after increasing the rotor speed, it is gradually reduced, while the component of the spectrum of current pulsations is continuously separated out with a frequency, the value of the frequency of rotation of the chotor ώ ₂ is fixed at the moment of the jump a significant decrease in the amplitude of the current component with a frequency a, to estimate the imbalance, the average frequency ω, and _r , □ о> is used as the rotational speed of the rotor