DE2644475A1 - METHOD AND DEVICE FOR MASS BALANCING ON ROTATING MACHINERY - Google Patents

Description

The invention relates to a method and a device for balancing masses on rotating machines, in particular a method of mass balancing that is suitable for large, high-performance steam turbogenerators.

It is often the case that a rotating part of a rotating machine is not complete or absolute is arranged symmetrically to its center axis, which leads to a somehow mass unbalanced state, in short imbalance called, leads. Such an imbalance causes a shaft to vibrate during operation of the rotating shaft Body. Vibrations that are too great cause one

309842/0606 8l- (A

abnormal condition of the bearings so that the shaft does not rotate normally. Additionally, that's this The force causing strong vibrations is considerably large and acts on the shaft in such a way that it is damaged or can be destroyed. A permissible tolerance value for the limit vibrations of the shaft is determined to avoid an accident due to the shaft vibrations. For this purpose, a rotating body is subjected to a rotation test. If the permissible tolerance value is exceeded, a counterweight or a counterweight is added to the rotating Body attached to reduce the degree of imbalance, thereby lowering vibration. This The procedure is called mass or weight balancing.

A steam turbine and a generator have a multiple bearing arrangement, in which a plurality of shafts, the opposite ends of which are supported in bearings, are coupled together. In general, it is customary to check the shafts individually for mass balance.

A mass balancing is carried out as follows:

(1) Measuring vibrations of a shaft at bearing points j

(2) Selecting leveling correction surfaces, d. H. from Places on a shaft to which balancing weights or weights are to be attached;

(3) Attach a test or proof weight to a correction surface and then measure its influence on the shaft vibrations; Determination of the shaft vibrations caused by a unit weight,

d. H. an influencing factor of the unit weight this result; 709842/0606

( ¹ O determining a balance weight in order to make the vibrations disappear by means of initial vibrations, ie shaft vibrations in the initial state, and by means of influencing factors;

(5) Attaching the weight thus determined to the correction surface of a rotating body. Operating the body in this state and check that the shaft vibrations fall within a tolerance range, thereby compensating is completed.

If a steam turbine generator that is in the manufacturer's factory manufactured, assembled in a power plant, a certain imbalance may occur. This requires one Compensation by rotating a shaft assembly. So far, a wave has been taken into account in such a case, which causes large shaft vibrations, and then the balance performed for the shaft in order to reduce the vibrations. Then there is a compensation for a wave, which causes the next largest vibrations. In a similar way, the waves are balanced out one after the other, creating the Shaft vibrations are reduced below an allowable value in order to complete the compensation.

In new, large, high-performance steam turbine generators, several shafts are coupled to one another, and these shaft arrangements influence each other, which leads to a complicated oscillation system. This makes it harder reduce the shaft vibrations below a given value. With conventional balancing, several balancing cycles are required to determine the factors influencing what requires a lot of time and is expensive. Even when a balance weight is determined, it is difficult to determine the type of estimate occurring vibrations until a balance weight is attached to the rotating body and then this

709842/0606

actually operated. Hence the determination of a balance weight unsure. On the other hand, when each shaft of a shaft assembly is balanced as in a power plant numerous operating cycles are required before equalization is fully completed.

The shaft vibrations are measured with a single vibration meter measured, which is fixed in one place. Therefore, only vibrations in the direction of the to be attached Vibration meter measured, d. H. Vibrations in one direction. With conventional balancing, there are vibrations measured in one direction only at one measuring point, so that vibrations in one plane, i.e. two-dimensionally, are not can be measured accurately. As a result, the vibrations used to calculate the balance are inaccurate and therefore exist a correction weight obtained is not an optimal value for reducing an imbalance on a shaft. With the conventional To compensate for this, improvements in terms of accuracy are still possible. In addition, a correction weight is determined by using less accurate vibrations, so that no optimal correction weight can be obtained, and therefore so far numerous equalization cycles are required before full equalization is achieved.

It is therefore the object of the invention to provide a method for mass or weight balancing that has the disadvantages avoids conventional methods and effectively reduces the amount of shaft vibration in a rotating machine; also a device for mass or weight compensation,

which avoids the disadvantages occurring when determining the correction compensation and the determination the correction weight as well as the measurements of the vibrations with great accuracy.

According to the invention, the shaft vibrations are determined by calculation that occur when an imbalance on the

109842/0606

equal shaft arrangement is present, and then becomes an influencing factor determined from the result achieved in this way. Then the initial vibrations are measured, and then a balance weight is used determined by using the measurements and the influencing factors obtained from the calculation. Additionally the shaft vibrations are estimated by calculation when a balance weight obtained in this way is attached if j then, it is confirmed that the shaft vibrations after the equalization turn into an allowable one based on the above results Range, and then finally a balance weight is determined. The balance weight obtained in this way will be on attached to a rotating shaft, which then operated for checking to complete the balancing of the shaft. The above method is excellent in the simultaneous reduction of all shaft vibrations with several

Speeds, such as B. numerous critical

Speeds and nominal speeds by adding balancing weights to balancing correction surfaces be attached.

The method according to the invention for balancing the masses for a multiple bearing rotor-shaft arrangement is characterized through the following process steps:

Determining a compensation influencing factor that represents the relationship between a unit weight and vibrations, if the unit weight is at a given compensation correction surface is attached;

Choosing compensation correction surfaces of the several times stored Rotor to which balance weights are attached;

Determine the balance weights in order to reduce residual vibration values using the least squares method to make small where-

109842/0606

where the vibration value depends on the initial vibration values, the influencing factors and the balance weights; and

Attaching weights corresponding to the balance weights to the balance correction surfaces so as to reduce the shaft vibrations to reduce.

The compensation influencing factor can be calculated from the structure of the multiple bearing rotor or directly from it Measuring the vibrations can be determined. Instead of the above weights, it is used to reduce shaft vibrations possible to determine compensating balancing weights in order to keep the sum of the plague oscillation value squares as small as possible that are multiplied by weighting factors derived from the square root of the square mean, des Vibration value and residual vibration values are preserved, and then to attach weights corresponding to the above compensating balance weights to the above compensation correction surfaces, whereby the shaft vibrations are reduced.

If the mass of a weight to be attached is limited, the above compensating counterweights are again compensated to be the sum of the residual vibration value squares, multiplied by the weighting factors obtained from the square root of the square mean of the Vibration value and the residual vibration value can be obtained, and from the product of the square value of the above compensating one Balance weights and weight-limiting factors (the factors that make the balance important of the weight) to be made as small as possible, and then weights are again compensated according to the above counterweights attached to the above correction surfaces to thereby reduce the shaft vibrations.

The inventive device for mass balancing for

109842/0606

A *

a rotating machine has a vibrometer for measuring the vibrations on the rotor shaft assembly and a electronic calculator that determines the balance influencing factors that determine the relationship between a unit weight and vibrations when this unit weight is attached to a given compensation correction surface, and then the compensation weights calculated so that the residual vibration values depend on the initial vibration values, the influencing factors and the counterweights are as small as possible.

The inventor examined a vibration state of a shaft in a plane perpendicular to the axial direction in a Vibration measurement position. It was found that the stiffness of a part carrying the shaft varies depending on the given Direction in the above plane changes so that the geometrical

s c he Ofp
rder vibrations in this plane is elliptical.

In other words, the vibrations change two-dimensionally in this plane.

The invention enables a powerful, accurate method for balancing masses and is characterized by the the following procedural steps:

Measuring the unbalanced vibrations that occur during rotation of a rotating shaft assembly, in two directions that intersect at right angles in bearing journals;

Analyzing the vibrations in rotationally synchronous components by means of a follow-up filter;

Determine optimal balance correction weights for reducing the unbalanced vibrations by means of a small electronic computer, being rotationally synchronous unbalanced vibrations as well as influencing factors are used, which were previously determined; and

109842/0606

Estimating the vibrations when the balance correction weights are attached.

The invention thus provides a method for mass balancing in a rotor-shaft arrangement ^for a primary engine, such as. B. Large high-performance steam turbines and generators. First, a compensation influencing factor is determined, which represents the relationship between a unit weight and a vibration when this unit weight is attached to a given compensation correction surface of a rotor supported by multiple bearings; then a compensation correction surface is selected to which a compensation weight is attached; then a balance weight is determined to make the residual vibration values as small as possible using the least squares method

is used, with the values of

the initial vibration values, the influencing factors and the balance weights depend. In this way, a weight corresponding to the above balance weight is applied to the above balance correctionf pool attached to reduce the vibrations in the shaft.

The invention is explained in more detail below with reference to the drawing. Show it:

1 shows a diagram to explain the method according to the invention for balancing masses in a rotating Machine,

Fig. 2 is a diagram for explaining the determination of a Balance weight,

3 shows a diagram for explaining a transmission matrix,

109842/0606

4 shows a diagram for explaining a vibration state,

Fig. 5 is a graph for explaining the relationship between Speed and amplitude,

6 shows a diagram for explaining a correction area,

7 shows a diagram to explain the balance weight for the secondary oscillation,

Fig. 8 partial representations of a rotating body with and 9 a gap for attaching a balance weight,

Fig. 10 curves for explaining the relationship between the speed and the vibration amplitude, which the advantages of show mass balance according to the invention,

11 is a diagram for explaining a method for mass balancing, which is particularly useful for reducing a large residual vibration value is suitable,

FIG. 12 is a diagram for explaining the method for mass balancing in order to have a balancing weight Reduce the cost of the residual vibration values when the balance weight obtained is very large is,

FIG. 13 is a flow diagram of an embodiment of FIG Invention,

Fig. I ¹ J details of a vibration sensor,

15 shows an axial section of a vibration sensor,

709842/0606

16 shows a section XIV-XIV in FIG. 15 at right angles to the shaft in a vibration-sensing position,

17 shows a representation with a geometric location of a deflecting rotation of a bearing,

Fig. 18 is a flow chart of the device according to the invention for mass balancing, and

19 compensation results obtained with the inventive Device can be obtained.

An exemplary embodiment of the invention is explained in more detail below with reference to FIG. The inventive method has the following procedural steps:

Determine factors influencing the relationship between weight and vibrations from the structure or description of the rotor represent;

Measuring the shaft vibrations that occur due to an imbalance;

Selecting compensation correction surfaces of the shaft on which Balance weights are to be attached; and

Determination of balancing weights to be attached to the balancing correction surfaces on the basis of the correction factors, obtained from the measurement results of the shaft vibrations and the calculation.

Then the balance weights obtained in this way are attached to a rotating shaft, which is then operated,

109842/0606

- Kf-

to confirm that the vibrations are reduced, whereby the weight or mass balancing is completed.

The following is the procedure for determining a balance weight explained in more detail with reference to FIG. In this process, a balance weight according to the method of least squares calculated to the

The sum of the squares of the residual vibration values after attaching the weights to the correction surfaces is as small as possible make, with the measurement results of shaft vibrations at numerous dangerous speeds, rated speeds or Speeds are used. Then will

after attaching the balance weights obtained in this way, the vibration values, d. H. the residual vibration values are calculated. If the residual vibration values fall within an allowable range, the balance weights thus obtained are used as final balance weights used. If the residual vibration values are outside the permitted range, the compensation condition is changed to allow the calculation of the compensation weights to perform again.

The invention is characterized by the determination of the balance weights taking into account the state of vibration after the counterweights have been attached.

Beforehand, a factor representing the relationship between a weight and the vibrations, i. H. an influencing factor, be calculated. For this purpose, a vibration characteristic is calculated that is present when an imbalance occurs in one of the A compensating correction surface of a rotating shaft is attached; then the amplitude of the vibrations in a vibration measuring position determined from the results thus obtained to be used as an influencing factor for calculating a balance weight to be used when a unit weight is attached to the counterbalance

109842/0606

ψ '

4h

Correction surface is attached. The vibration characteristic of a Shaft arrangement can be calculated using values that depend on the construction of a rotor, such as: B. the Dimensions of a shaft assembly, the weights of bearing parts during rotation, the bearing condition, such as, for. B. Properties an oil film.

The analysis of a shaft arrangement can be carried out by means of a transmission matrix. This procedure will carried out as follows:

A shaft arrangement is divided into elements such as into a shaft part of concentrated mass and into a coupling part by means of a spring. Then there is the vibrational system

according to Fig. 3 ctus::

a value matrix. JXj from values such as e.g. deflection, deflection angle, shear stress and

• moment in the subdividing digits, and an element transfer matrix ΓαΙ, which shows the relationship between the Represents values of the elements.

With deflections Vx, Yx (cm), deflection angles θχ, Gy (rad), Shear stresses Vx, Vy (kg) and bending moments Mx, My (kg cm), the value matrix KJ is given as follows; (x = values for horizontal vibrations and y = values for vertical vibrations):

M =

V ί L J ■ H ~ Μχ
My_ θ
M. / Qi V W. = Vx
Vy 709 842 ) 06

rexl

4 *

The transmission matrix | [a3 can be calculated by the elements will. For example, the transfer matrix ΓαΙ for the

C- h ^ y j, carrier ι - horizontal vibrations of a wave element with a uniform cross-section given as follows:

M =

o <C ₃ ex

ß_2 OfI ⁰ I

«Ic IC.

ß_

^C 2 1 ^C 3

= | · (Cosβ + cosβ), C ₁ = - | _ß (sinhß + sinß)

C ₀ = -5- (coshß - cosß), C, = -5- (sinhß - sinß)

EGG

with 1 = E = = ω - / ^{u =}

Length (cm), modulus of elasticity (kg / cm ² ), geometric moment of inertia (cm), angular frequency (rad / s), and

2 mass per unit of length (kgs / cm).

fO9842 / 0606

The matrix of the value £ yJ before and after this element is given as follows:

n + l

Vx θχ Mx Vx

n + l

Vx θχ Mx Vx

The transfer matrix [jCJ for a concentrated weight is given as follows:

1 0 2.2 0 0 0 0 1 0 0 0 1 0 muO ² 0 1

with m = mass (kgs / cm),

i = radius of gyration (cm), and
{* ■> = angular frequency (rad / s).

At the point where the imbalance acts, the shear stress decreases due to the imbalance caused Centrifugal force too.

In this case, the boundary condition at the shaft end is free. Then a force matrix [Y] such as B. the forces and

T09842 / 0606

ψ -

Ai

264U75

Moments

Low values, to zero

DQ

One way of calculating an oscillation amplitude with regard to forced oscillations is given below explained. It is assumed that the oscillations follow a sine curve with an angular frequency Co (rad / s). The oscillation amplitude is a vector with a magnitude and a phase. A complex number is now used to To represent values with such a magnitude and phase. As a result, the elements of the matrix with the value yyfJ and of the transfer matrix [A] represented by complex numbers.

The matrix of the value (VL at one end is expressed by an unknown matrix \) t ~] using the boundary condition in its place:

■ y " Λ "d" I. O X 1 P. O O 1

(D

I = identity matrix, and X = unknown matrix.

in | ^X ] UJ

The term (Yj in | ^X ] and [ ^Y | in equation (1) represents

LJ

represent the values that have no relation to the unknown matrix [Y] at the edge when calculating a transfer matrix, such as B. a vibratory force acting on a vibration system .

* 09842/0606

- ψ-

The transfer matrix for a particular element and

the matrices of the values , of which the

L ¹ JL ¹ J _{n + 1}

following relationship:

n + l

The transformation or transfer matrix ΓαΙ can

for each element can be calculated so that from the equations

Γυ7 (1) and (2) the matrix of the value in each place as

W _n

a function of a matrix
can:

-Cl

can be expressed as follows

From equations (2) and O) it follows:

n + l

n + l

= [A] Cb]

η η

It follows:

= Ca] ♦

n + l η

£ 09842/0606

-yi -

Y = [B] 1 X 1 1

Then this equation and equation (1) determine the value

from [ß] : 1

I. O O O O 1

[bTJ. can be calculated using the transformation matrix j_Aj η

and equations (4) and (5) are used. Accordingly, can Lβj can be obtained from equation (3) by dividing the matrices of the values [y] at respective points as puncture of an unknown Matrix are adopted.

L ¹ J

Given the matrix of value:

at the other end is as follows

On the other hand, the condition P = O can be obtained from the constraint at this point, so that an equation related to an unknown matrix JJC ^- ] is obtained. In this way, \ x] can be obtained from solving the above equation:

109842/0606

-ψ-

Y N D. ₁ P.

'12 '22

C ^C

21

X
1

Equation (3) is replaced by the unknown matrix [x] obtained in this way in order to calculate the value of the matrix \\ ~] at the respective positions. In this way, the oscillation amplitude can be achieved for the entire oscillation system.

Compensation correction surfaces are chosen by adding vibration properties a shaft arrangement can be used. For this purpose, the vibration property of the shaft assembly calculated if there is an imbalance attached to it in order to use the results to be obtained. The Fig. * J shows the Oscillation state at a natural frequency of the shaft, which is supported at its opposite ends. The vibrational state at the first to third natural frequency is such that the directions of the primary vibrations over the entire length of the wave remain the same that the amplitude of the secondary oscillation is smallest in the middle of the wave, the directions of oscillation are reversed at the opposite ends, and that the direction of the tertiary vibrations is in the middle of the shaft in one direction and at opposite ends of the shaft in the other direction.

£ 09842/0606

The rotating machine tends to vibrate due to an imbalance during operation. The vibrations of this type increase or decrease with increasing speed (cf. FIG. 5). The rotating shaft has its own speed that does not cause vibration, and this speed is called the critical speed. As shown in Fig. 5, there are three critical speeds. These are referred to as the first, second and third critical speed, respectively. The oscillation conditions in these critical speeds correspond to the vibration characteristics of a shaft assembly shown in Fig. ¹ J.

By means of the vibration properties of those shown in FIG Shaft arrangement are the compensation correction surfaces from the measurement results of the vibrations in a Wave determined. A case will be explained in which the vibrations at the second critical speed are large and the Vibrations at the first and third critical speed are small. First, it is assumed that five compensation correction areas A to E in FIG. 6 are present. The compensation correction areas, which are effective for the second critical speed are close to the opposite at A and E Ends of the shaft. Therefore, it is advantageous that the directions of the weights are opposite to each other applied to the two Compensation correction surfaces 13 are to be attached (see. Fig. 7). In this way, the vibrations at the second critical ' Speed can be reduced, which now has no adverse effect on the vibrations at the first critical Exercise speed except at the second critical speed.

In the method for mass balancing according to the invention, weights are determined in such a way that the vibrations under them Reduce conditions by using data relating to numerous critical and rated speeds. In other words, an attempt is made to reduce the shaft vibrations

^ 09842/0606

ψ '

reduce at all critical speeds, such as B. the first, the second and the third critical speed. The calculation method used uses the least squares method to calculate the sum of the squares

To make vibration values as small as possible after attaching the weights, d. H. the residual vibration values to the shaft vibrations to reduce the number greater than the number of compensation correction surfaces. The residual vibration value is like it follows given:

N
n = l

£ = A + Y ^ CK V _n (6)

m m ■ £ --- * mn η

with £ = residual vibration value,

A = initial vibration value,

ex = influencing factor,
mn

W _n = weights on the respective compensation correction surfaces,

η = number corresponding to the places of the compensation correction areas I ¹ U η "Ξ.Ν,

N = number of compensation correction areas,

m = number corresponding to the measuring points and conditions of shaft vibrations, and

M = product of the number of measuring points and measuring state.

An estimation function is used to calculate the balance weights as follows:

M, IP

^J = ΣΓ Kl ² (7).

m = l

109842/0606

A balance weight W is bedded under the condition

it is true that the function J is as small as possible. For this purpose, the puncture J is partially differentiated according to W,

and then the value obtained in this way is set equal to Mull:

aj aw

= ο

This becomes an equation for calculating ¥ like

CX

is obtained as follows:

¹ W [a]

Λ j

(X

CX

IN

(X
- Ml '* (X
MN (X
: 11 "' (X
Ml "in ·' c <
MN

^A i

(9)

Column vector of a balance weight

Matrix of an influencing factor

transposed matrix of an influence function ° <

Column vector of an initial oscillation value.

The vibrations after attaching the thus obtained Aus-Jhsgewichts, ie
can be determined as follows:

equilibrium, d. H. a residual vibration value <T, can like

£ 09842/0606

M.
Hi

with W = balance weight, and
£ = residual vibration value.

The residual vibration values are calculated for all vibration values that are used to calculate the balance weights are used, and if these residual vibration values are below the permissible vibration value, that of the size of a Depends on the shaft, the weight is used as the required balance weight.

If the residual vibration values are not below the allowable value, the condition for the compensation, such as. B. the compensation correction areas, changed, whereupon a new one A balance weight is calculated.

In this way the balance weight is determined and then attached to a rotating shaft. This is a Part of a wheel disc 32 is provided with a gap 33 for attaching a weight, and then the weight is in the Gap 33 is inserted in the direction specified by the direction of the gap 33. If no disc 32 is provided, has a shaft 31 a gap 34 for attaching a weight (see. Fig. 9), and then the weight is fitted into the gap 3 ^.

After attaching a balance weight to the rotating shaft, it is put into operation to check that the shaft vibrations are reduced, whereby the balance is completed.

109842/0606

This method allows a reduced number of

^ before. ^ nnren
CompensationSJ to reduce shaft vibrations at all critical speeds and nominal speeds in a shaft arrangement including several coupled shafts. This creates a very economical rotating machine.

Fig. 10 shows an example with compensation test results for a model rotor. Two curves represent the Changes in the vibration amplitude due to the speed at a certain point before and after equalization. In In this figure, critical speeds occur at two points. Using this procedure, a balance weight is created determined from vibrations prior to balancing, and then the weight is attached to the shaft to compensate for the shaft vibrations to eat. The result is shown as a "after equalization" curve. With this compensation, the shaft vibrations can be reduced to 1/5 according to a balancing process. In the exemplary embodiment, the shaft vibrations are on 1/10 decreased. Even if the shaft vibrations are 10 times as large as a permitted value, the shaft vibrations can can be reduced to a permitted range with a single equalization process. Therefore, with the invention the shaft vibrations can be effectively reduced with a single compensation process.

If in the above embodiment, after attaching the balance weights, the residual vibration values outside a allowed range, the calculation conditions should be changed again to perform the calculation. the Fig. 11 shows a method of compensation in such a case. First, a balance weight corresponding to a Principle calculated according to the method of least squares, the sum of the squares of the residual vibration values as possible

109842/0606

to be made small by using various vibration data such as B. critical speeds and nominal speeds, and then the residual vibration values are calculated when the weight thus obtained is attached. When the residual vibration values are smaller than the permitted value, the weight determined in this way is used as the balance weight. When the residual vibration values are greater than the permitted value, the calculation is repeated, with the large residual vibration values in particular must be taken into account in order to reduce this.

The following equation is used as an approximation in place of equation (7):

J = ΣΙ

M ₂

m = l

with £ - = residual vibration value, and

Λ = factor.
m

The factor λ in equation (11) initially equals 1 m

taken.

The result of this calculation agrees with the result from equation (7).

The calculation is carried out for a balance weight in the first cycle, and if the residual vibration values are not less than the permitted value, the factor A _{m is determined} according to the following equation:

909842/0606

R m

V "

λ (i

P ² \ i "
^£ m ^A m

/ R

(12),

= Residual vibration value,

= Factor that is used in the previous calculation for a balance weight,

= Factor for calculating a balance weight for the next balancing,

= Product of the number of measuring points and the number of measuring conditions.

A balance weight is calculated using the X thus obtained. By repeating this calculation, m

a balance weight can be determined so that in particular a large residual vibration value is reduced.

If the balance weight obtained is very large and the residual vibration values also have certain permissible limits and can increase, the calculation is repeated for a balance weight in order to reduce this at the expense of the residual vibration values.

Fig. 12 shows a method used in this case. First, numerous vibration data, such as z. B. critical speeds, rated speeds, used to make a balance weight using the least squares method

to calculate that makes the sum of the squares of the residual vibration values as small as possible,

109842/0606

and then the residual vibration values are calculated when this weight is attached. When the received balance weight is extremely large and there is a certain permitted range, a balance weight is recalculated in order to reduce it to a certain extent at the expense of the residual vibration values. An estimation factor according to equation (7) is given by:

kJ ² X

n = l

(13),

with £ = residual vibration value,

W = weights for the respective compensation correction areas,

5 = factor given as data value,

N = number of compensation correction surfaces, and

A = pactor.

A balance weight is determined in this way, and so a desired balance can be achieved, with a there is a reduced balance weight.

Another method for determining the balance correction areas by determining a balance weight will now be described explained.

In other words, numerous types of conditions are determined and then a balance weight is established for determines these conditions, after which the best balance weight is used as the final balance weight. There are z. B. numerous compensation correction areas accepted; then will several compensation correction surfaces selected from among these, so that a compensation weight corresponding to that explained above Procedure for a case can be determined by an apprenticeship

109842/0606

equilibrium is attached to this compensation correction surface. The best balance weight is chosen among these. The conditions for determining the best balance weight are such that a residual vibration value is small, a balance weight is small and the number of compensation correction areas is small.

The method explained above is shown in FIG. In other words, when the initial vibration value A is larger than an allowable value, a weight is obtained by as much as Residual vibration value £ through

to make it as small as possible.

If the residual vibration value £ ■ is greater than er deciduous value, then will

^m l ^Λχη

Made as small as possible in order to obtain a weight that reduces the residual vibration value.

If the mass of a weight is limited, then will

M _o N

Sl ^e -I ^{2 λ} » ⁺

Made as small as possible in order to obtain a compensated weight.

109842/0606

264U75

1 * 1-16 show a method for detecting a vibration for a device according to the invention.

A wave oscillation measuring rod 51 consists of (i) a hollow cylindrical _{outer housing 53, (ü) a vibration sensor 5 * 1 and a tip 55}} which are attached to the upper and lower ends of a contact shaft 52 which extends in the direction of the length of the outer housing 53 movable therein, (iii) a coil spring 56 and a downwardly holding member 57 between the outer housing 53 and the contact shaft 52 to bias the tip 55 with an appropriate pressure, and (iv) from a lock 58 near the Schviingungsfuhlers 5 * 1 on the contact shaft 52, v.obei the lock 58 for setting the

Cspring
Tension of the screw ³ 56 is suitable.

Fig. 15 explains the vibration measurement in the shaft with the shaft vibration measuring stick 51 explained above. The outer housing 53 for the rod 51 is arranged so that it is through a rod opening 67 in a bearing cover 66, then penetrates through a rod opening 6 * 1 in a bearing cover 63 and then through a rod opening 62 in a bearing bush 6l; then the tip 55 at the lower end of the contact shaft 52 is brought into pressure contact with a rotating shaft 60. Afterward the upper end of the outer housing 53 is fastened to the bearing cover 66 with a bolt 72. A piece of metal 70 is attached attached to the bearing cover 66 by means of a bolt 77 and then attached to a ball socket 70 passing through the center the upper and lower spherical bearing surfaces 68,69 is supported.

Two of the rods 51 explained above are attached to the circumference in the same area at a right angle to each other, as shown in FIG. Vibrations at two points A and B can be measured by means of rods 51

09842/0606

those that intersect at a right angle, the Points A and B are angularly spaced in the circumferential direction of the rotating shaft 60 by 90 °.

The vibrations χ and y at points A and B at a certain speed can be expressed as follows:

x = IxI sin (Wt + θχ)

• (14), y = jy J sin (Lot + 9y)

where I χJ, I y | , θχ, 9y the amplitudes and phases at the Represent points A and B and are the values to be measured. In general, when rotating horizontally Engine of a turbo generator die

Vibration properties in points A and B changed due to the anisotropy of the bearings, so that the amplitudes I x | and I change yI in the equation. This is why it describes the rotating shaft 60 at a given speed

,.,. r_. i geometric ; .

an elliptical belt if (x, y) is plotted and UJt

(Ge ometric > is taken as a parameter. This elliptical shape changes

its shape with speed. In other words, an angle between the x-axis and the y-axis changes. The fig.

(geometric ;
Figure 12 shows a test of a deflecting rotating shaft 60 at a hazardous speed and rated speed that were actually measured. Bearings 100, 101 are provided. Since the deflection of this wave assumes the shape of an ellipse, the measuring direction should not be restricted to one direction. Otherwise, vibrations near the minor axis of an ellipse can be measured as a peak vibration due to a change in the direction of the major axis of the ellipse, although the measurement relates to the vibration in one of the largest amplitudes

70984 2/0606

should take a permissive stance, d. H. the position close to the ellipse. On the other hand, if the measurement of the Given vibrations in two directions, the above-mentioned disadvantage can be avoided, at least one Point the vibrations in the vicinity of the main axis of the ellipse are recorded. This leads to a very precise measurement of the vibration conditions a rotating shaft 60 corresponding to the bidirectional vibration measurement.

In general, the rotating shaft 60 has an unbalanced mass, and therefore this unbalanced mass is called a centrifugal force, which in turn causes unbalanced vibrations in the rotating shaft 60. If the unbalanced vibrations become very large, the rotating shaft 60 touches the bearing bush 61, resulting in damage or destruction of the rotating shaft 60 leads. For this This is because it is necessary to reduce the unbalanced vibrations occurring in the rotating shaft 60. on this way, compensation is required to reduce the imbalance. For an efficient, very precise compensation the vibration data should be measured very precisely.

The bidirectional vibration measurement explained above enables a very precise determination of the compensation correction weights (weight with mass and angle).

The following is the procedure for determining the compensation

Correction weights described. With the influencing factors # _,

(K)
C * _mn (n = 1, 2 ...; N = number of compensation correction

surfaces; m = 1, 2 ...; M = number of measurements; V = vertical direction; H = horizontal direction) and the initially unbalanced oscillations ^A _m » ^A _m results for the remaining

7 09842/0606

4- ρ (ν) e

vibration values c ^v ', <-

(V)

(H)

m m ^ ri mn η

(15)

^ function The following paragraph; ^ j is determined so that the

Vibrations β, ^. be reduced:

m J

(16),

= Weight factors.

Assuming that the weight factor is 1, an optimal correction weight is given as follows to be the To make function j as small as possible:

opt

T
Of A

(17)

09842/0606

(X

mn

mn

^(H)

mn

CX

mn

mn

^(H)

mn

(m

(18)

ra =

(V) η

mx

(V)

(H)

mx

(H)

my

(m = 1,

W =

Fig. 18 shows a flow chart of the invention Device for mass balancing.

The vibrations at points A and B ₃ which were detected by the vibration sensor 54 are fed to a follow-up filter. The oscillations are analyzed in rotation-synchronous-unbalance-oscillation components by this tracking filter. These unbalanced vibration components are printed as output signals by a typewriter in a data processing system for monitoring the vibration data. In the meantime, the influencing factors that were previously determined at points A and B are fed into a small electronic computer. In addition, speeds that generate vibrations too high, ie vibrations at points A and B at a critical; Rotational speed and a rated speed, i ⁿ the small electronic computer input, to

709842/0606

determine the compensation correction weights by means of equation (18). Then the residual vibration values are sent to the Points A and B are calculated when the above balance correction weights are attached, after which it is confirmed that the vibrations stay in a permitted area. If the vibrations are outside of this allowable range, the compensation correction surfaces is changed, and then the calculation is repeated in the above manner until the residual vibration values in fall within the permitted range. The small electronic computer can also be provided in the data processing system.

The following are the results of an actual compensation by means of the vibration measuring device explained above shown.

If the speed of a rotor is increased, an excessive unbalance occurs in bearings No. 1 and No. 2 (see Fig. 19a) at opposite ends of the rotor. There are two ways to reduce these excessive unbalanced vibrations of compensation attempts before:

(1) Measurement of the vibrations in one direction (vertical direction),

(2) Measurement of vibrations in two directions (vertical and horizontal directions).

Fig. 19 shows the results of the mass balancing of the bearing 2 in the horizontal and vertical directions.

Ϊ098Α2 / 060Β

Claims (5)

Claims .I). Procedure for mass balancing on multiple bearings Motor shaft assemblies ,, marked by Determine a compensatory influencing factor that will affect the relationship represents between a unit weight attached to a given compensation correction surface and vibrations, Selecting a compensation correction surface of the multiple bearing Rotor for attaching a balance weight to this, Determination of the balance weight in order to determine the balance influencing factors depending on the initial oscillation values and to make the balance weight as small as possible using the least squares method, and Fix your weight according to this balance weight on the compensation correction surface in order to reduce the vibrations in the shaft. 2. Method of mass balancing for rotating machines, characterized by Determine a compensatory influencing factor that will affect the relationship between one at a given compensation correction surface represents fixed unit weight and vibrations, 7 09842 / 060S Selecting a correction surface for the multiple bearings Shaft for attaching a counterweight to this correction surface, Determination of the balance weight in order to determine residual vibration values depending on the initial vibration values, compensation influencing factors and to make the balance weight as small as possible using the least squares method, Find a compensating balance weight, multiplied by the sum of the squares of the residual vibration values with weighting factors to make it as small as possible, by the ratios of the residual vibration values to the square root of the root mean square of the residual vibration values are and Attaching a weight corresponding to the compensating balance weight to the balance correcting surface to to reduce the vibrations in the white. 3. Procedure for mass balancing for multiple bearing shaft arrangements, characterized by determining a balancing influencing factor that the relationship represents between a unit weight attached to a given compensation correction surface and vibrations, Selecting a compensation correction surface of the multiple bearing Rotor for attaching a balance weight to the balance correction surface, Determination of the balance weight in order to minimize residual visual vibration values using the method of least squares % 09842/0606 to make, with the residual vibration values from the initial vibration value, the influencing factor and the balance weight depend. Find a compensating balance weight, multiplied by the sum of the squares of the residual vibration values to make it as small as possible with weighting factors that result from the ratios of the residual vibration values to the square root the root mean square of the residual vibration values are determined, Compensating the compensating balance weight again in order to make the sum of the squares as small as possible the residual vibration values, multiplied by a weighting factor, and a product of the square root of the compensating Weight and a weight constraint factor (which represents the degree of importance of an imbalanced weight, and Attaching a weight corresponding to the compensated counterweight to the compensation correction surface to reduce the vibrations in the shaft. 4. Method for mass balancing for rotating machines, characterized by a vibration meter for measuring vibrations in the multiple bearing-mounted rotor-shaft arrangement, an electronic calculator for calculating a compensation influencing factor, which represents the relationship between a unit weight and vibrations when the unit weight attached to a given offset correction surface 509842/0606 is, as well as a balance weight, to the residual vibration values depending on an initial vibration value j the influencing factor and the balance weight if possible to make it small. 5. Mass balancing device for rotating machines, characterized by a vibration meter for measuring vibrations in a bearing of a rotating shaft assembly in two Directions, a data processing device and a frequency analyzing device to determine a rotationally synchronous component, and an electronic computer for calculating a compensation influencing factor, which is the relationship between a unit counterweight attached to a given counterbalance surface and represents vibrations, as well as a balance weight to determine residual vibration values in two directions (e.g. vertical and horizontal direction) ■ depending on the initial vibration values, the influencing factor and the To make the balance weight as small as possible. 09842/0606