This standard specifies the test methods and conditions for the static natural frequency of steam turbine blades (static frequency) and the natural frequency of the blade in the rotating state (dynamic frequency). This standard is applicable to the testing of static and dynamic frequencies of steam turbine blades. JB/T 6320-1992 Frequency measurement method for steam turbine blades JB/T6320-1992 Standard download and decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
Frequency measurement method for steam turbine blades
1 Subject content and scope of application
JB/T6320—92
This standard specifies the steam turbine blades Static natural frequency (static frequency) and the natural frequency of the blade in the rotating state (moving cheek test methods and conditions.
This standard is applicable to the test of static frequency and dynamic frequency of steam turbine blades. 2 Reference standards ||tt| |JJG262
JJG349
JJG180
GB6586
GB12181
GBJ1461
General Oscilloscope Verification Regulations (Trial)
General Verification Regulations for Electronic Counters (Trial Implementation) Verification Regulations for Quartz Crystal Oscillators in Electronic Counters (Trial Implementation) Technical Conditions for General Cathode Ray Oscilloscopes
General Technical Conditions for Low Level Signal Generators
General Technology for Spectrum Analyzers Conditions
ZBK54018 steam turbine main parts (rotor part) processing and assembly technical conditions JB3073.4
3 technical requirements
3.1 test instruments
precision forging moving blade technology for steam turbines Conditions
3.1.1 Test instruments should use oscilloscopes, low-frequency signal generators and spectrum analyzers that comply with GB6586, GB12181 and GB11461 specifications respectively. Other test instruments with equivalent accuracy can also be used. 3.1.2 Oscilloscopes and counters It should be calibrated according to JJG262, JJG349 and JJG180 regulations respectively. 3.2 Static frequency test
3.2.1 Personnel requirements
Question rate testers must be trained and undergo regular qualification review. 3.2.2 Test conditions| |tt||3.2.2.1 Single blade test conditions
a.
b.
e
d.
e.||tt| |The blades to be measured should be inspected and qualified.
A hydraulic ticket with adjustable clamping force and a hydraulic system anti-testing bench, or other similar workbench, should be designed and processed with high accuracy. Comply with the requirements of the rim pattern. When the blade is installed on the impeller for testing, it must be installed correctly according to the product drawing and process requirements. The tightening degree of the blade root should be consistent with the newly designed cheek-adjusted free blade. Samples and rate test cards should be established (see Appendix A). and Appendix B). 3.2.2.2 Grouped blade test conditions
The tested blades shall pass the inspection and be correctly installed on the impeller according to the product drawing and process requirements a.
Grouped blade connection. The installation of parts should comply with the requirements of the product drawing. The tightness of the blade root of the tight-fitting blade should be the same. b.
Full circle (A-shaped) connecting blade test conditions
3. 2. 3
Ministry of Mechanical and Electronic Industry 1992--06--26 Approved 80
1993-01-01 Implementation
JB/T6320-92
a. Entire Each component of the ring (mesh) connection blade should be inspected and installed correctly according to the product drawing and process requirements. b. The tightening degree of the blade roots of tight-fitting blades should be consistent. 3.2.2.4 The joint surface of the loose blade root and the impeller can be correctly fixed with adhesive. 3.2.3 The quantity to be measured
According to the technical requirements of the product drawing, measure the particle rate value of the type to be measured and reported. 3.2.4 Test method
3.2.4.1 Self-moving method
The self-exploring method refers to the method of measuring the inherent rate of the blade when it is in a free attenuation state. The self-oscillation method is generally used in the tangential direction A of the moving blade (group). Rate determination of type perturbations. It can also be used to measure and check other reporting rates of single blades.
b． The direction of the excitation chain strike should be consistent with the vibration direction of the blade under test. C
When testing, adjust the output frequency of the signal generator so that the Lissajous figure of the oscilloscope is a clear and stable circle or a dilated circle. At this time, the output frequency value of the signal generator is the Inherent grain rate. d. The self-report method test system is shown in Figure 1. 3.2.4.2 Resonance method
The resonance method refers to the method of measuring the natural frequency of the blade when it is in a strong resonance state. The a-co-movement method is suitable for the determination of particle rates of various vibration shapes of moving blades (groups) and gear trains. b. Installation of the vibrator
The placement of the exciter should be such that the generated excitation force is consistent with the vibration direction to be measured of the blade (group) without affecting the correct measurement of the blade regularity,||tt ||Yong wave device
Yx
report picker
.
Low frequency signal generator
Figure 1 block diagram of self-oscillation method test system
c. Measurement of pre-rate
Digital frequency meter
By vibrator Generate a certain excitation force and apply it to the blade under test, and adjust the output rate of the signal generator so that the Lissajous figure of the oscilloscope is the circle with the largest amplitude; fine-tune it near this frequency value. If the phase evolves, the maximum amplitude is used. The output frequency of the signal generator at this time is the frequency of a certain vibration mode of the blade. By continuously adjusting the output frequency of the signal generator, the frequencies of other vibration modes can be measured in sequence. d. The resonance method test system is shown in Figure 2.
3.2.4.3 Spectral analysis method
Spectral analysis method refers to the method of using fast Fourier leaf (FFT) analyzer to measure the natural frequency of each vibration mode of the blade in the free attenuation probe state.
a.
The spectrum analysis method is suitable for the determination of frequencies of all vibration types. b. According to the needs of the measured vibration shape, select the appropriate excitation hammering direction. e
Before testing, place the forehead spectrum analyzer on the forehead domain linear spectrum, and select the forehead rate range appropriately according to the resolution. Refinement techniques can be used when necessary to meet the measurement error requirements specified in this standard. 81
d. Measurement of the reporting rate of each stage
picker
JB/T6320-92
quilt carrier
Yx||tt ||o
power reason
large device
low question signal generator
mathematical question rate meter
Figure 2 Resonance method test system frame | |tt||Using fast conversion technology, the peaks of each order of the frontal domain linear spectrum are instantly increased, and the particle rate of each order of operation modes can be measured simultaneously by hammering the blade once. If necessary, the contour data can be recorded with a plotter or visual preprinter, and the vibration shapes of each order can be checked. The frontal spectrum analysis method test system is shown in Figure 3. Matcher
3.2.5 test
3.2.5.1 single blade test
acid belt
recorder
spectrum
analysis Instrument
Figure 3 Spectrum analysis method test system block diagram
Plotter
a, before the test, according to the content of the blade test card according to the provisions of 3.2.2.1.e, use The test system is calibrated with the sample piece, and the clamping and measurement are repeated at least three times, so that the error between the measured rate value and the rate value of the sample piece is not greater than 1%. b. For frequency testing of the first blade without creating a sample, please refer to Appendix A. 3.2.5.2 Group time slice irrigation test
8. During the test, select a group of leaves and conduct a vibration test using the co-photography method. Correctly measure the frequency of the required vibration mode according to 3.2.4.2.C. Based on this, measure the frequency of other blade groups. b. The pickup should be placed in a more sensitive test plane. 3.2.5.3 Whole (mesh) connected blades To test the whole (mesh) connected blades, it is necessary to measure the frequency of reporting the pitch diameter mainly in the tangential direction, and the number of measured pitch diameters shall not be less than 6. 3.2.5.4 Wheel System vibration test
The gear system vibration test needs to measure the rate of axial pitch diameter vibration, and the number of measured pitch diameters is not less than 6. 3.2.6 Data recording format
3.2. 6.1 The recording format of single blade top rate data is as shown in Table 1 and Table 2.3.2.6.2 The recording format of group blade top rate data is as shown in Table 3 and Table 4, 3.2.6.3 Full circle (mesh), gear system reporting blade bottle The rate data recording format is shown in Table 5. 82
3.3 Dynamic frequency test
3.3.1 Test preparation
JB/T 632092
3.3.1.1 All test blades (group ) shall pass the inspection and be correctly installed on the impeller according to the product drawing and process requirements. 3.3.1.2 (Test) The design, manufacture and assembly of the impeller shall comply with the product drawing and process requirements. 3.3.1.3 The blade connectors should pass the inspection and be assembled correctly according to the production pattern and process requirements. 3.3.1.4 Before testing, the static number of the blades (group) should be measured (or temperature measured) in detail. 3.3.2 Measured quantity
According to the product drawing and design requirements, measure the moving frequency and phototype of the moving blade. 3.3.3 Test methods
The test methods recommended by this standard are divided into current loop method and forced test method according to the signal transmission method. 3.3.3.1Basic requirements
Table 1
Single blade static frequency test record
Product code
Installed power plant
Blade model
Blade root Type
Class
Type
Number of blades
Blade height mm
Rotor diameter mm
Instrument used: ||tt| |Test
Audit
Operating temperature ℃
Test method
fmaxHz
fmin Hz
Excitation rate dispersion
%
rate qualified range
Hz
factory number
th
year month day
Taiwan
83|| tt||Sequence
84
Blade number
No.
Display rate
Hz
JB/T 6320-92||tt ||Table 2
Quality
Disk
kg
Sequence
No.
Blade No.
Frequency||tt ||Hz
Quality
kg
Blade model
Blade root type
Level
Number of blades
Leaf Height
Rotor diameter
mm
mm
Group condition
Use only table:
Test
JB /T6320—92
Table 3
Group blade static frequency test record
Product code
Installed power plant
Operating temperature
℃
Test method
fmaxHz
fminHz
Rate dispersion %
Rate qualified range Hz
Audit
Year
Factory number
No.
Taiwan
85
Sequence
No.
86
Blade Group number
Group
Number of blades
Particle rate
Hz
JB/T6320—92
Qiu 4||tt| |Sequence
No.
Blade group number
Group
Number of blades
Rate
Hz
Blade model
Blade root type
Class
Type
Blade number
Blade body height
Instrument used:
mm| |tt||Number of pitches
Test
a.
b.
JB/T6320—92
Table 5
entire Ring (mesh), gear train vibration static frequency test record product code
Installation power plant
Rotor diameter
mm
Group status
Connection method
Operating temperature
℃
Test method
Rate
Hz
Audit
Number of pitches||tt ||Factory numberbzxz.net
No.
Year and month
When using a piezoelectric crystal chip as a moving frequency measurement sensor, the piezoelectric crystal chip should be phase calibrated.日
frequency
H
台
When using resistance strain gauge as a sensor to measure dynamic frequency, the resistance value can be anywhere from 350 to 10000. Choose a strain gauge with small dispersion and high sensitivity.
C
d.
refers to application,
e.
The sensor must be pasted (encircled) with strain glue according to process requirements, and use thin The steel sheet is shielded and protected. The leads used for dynamic frequency testing should be shielded wires, and all leads must be fixed. During the actual measurement in the power plant, the waterproof strain protection glue should also be able to meet the test temperature and fatigue strength requirements. The measured rate value should be corrected according to the working temperature of the blade. 3.3.3.2 Current ring method
The current ring method refers to the method of using a current collector to transmit the vibration signal of the rotating blade to the measuring instrument to measure the motion. . The current collecting loop method test system is shown in Figure 4.
87
a.
JB/T6320—92
Supervisory transfer requires points
Stream R
Static
Circular speed device
tse
feed generator
Fangtian 2
feeding record only
Figure 4 block diagram of current loop method test system| | tt | One type is the mercury-type collecting ring, which should be strictly sealed during use to prevent mercury leakage. b. During the test, according to the test requirements, the excitation source can use piezoelectric body pieces, permanent magnets, AC and DC electromagnets, pressure gas, pressure liquid, etc.
c During the test, the rotation speed must be accurately measured, and the rotation speed signal, perturbation signal and blade operating temperature must be recorded at the same time. The recording speed of the recorder should be selected reasonably to ensure measurement accuracy. 3.3.3.3 Telemetry method
The telemetry method refers to using a sensor attached to the blade to transmit the vibration signal of the rotating blade through a transmitter fixed on the rotating part, and then receive it by a receiving antenna mounted on the stationary part. Then, it is passed to the measuring instrument to measure the dynamic frequency. The telemetry test system is shown in Figure 5. | |tt | Block diagram
Installer
Specialized equipment
When selecting a transmitter, the main technical indicators of the transmitter, such as signal-to-noise ratio, sensitivity, frequency response and wet drift, should meet the dynamic measurement requirements need.
The transmitter should be tested before use, and its working performance must be stable. b.
c Correctly choose the relationship between the transmitter carrier frequency and the length of the transmitting antenna to prevent dead zones. The carrier frequency between the transmitters used at the same time should not be less than 1.5MHz.||tt ||d. The transmitter power supply can be battery power or induction power. When using battery power, the working environment temperature should be strictly controlled to ensure normal operation of the battery.
88
The transmitter power supply can be battery power or induction power. When using battery power, the working environment temperature should be strictly controlled to ensure normal operation of the battery.
88
The transmitter power supply can be battery power or induction power. When using battery power, the working environment temperature should be strictly controlled to ensure normal operation of the battery.
88

JB/T6320—92
Monitoring needs to be divided
flow R
static
circular speed device
tse
feed guide generator
release day 2
into the belt record only
Figure 4 Slip ring method test system block diagram
number processing point
This standard recommends two types of slip rings, one is the kidney ring slip ring, when using, the materials of the slip ring and carbon fiber should be correctly selected, and the structural design should be reasonable; the other is the mercury slip ring, when using, it should be strictly sealed to prevent mercury leakage. b·During the test, according to the test requirements, the excitation source can be piezoelectric body, permanent magnet, AC and DC electromagnet, pressure gas, pressure liquid, etc.
c During the test, the speed must be accurately measured, and the speed signal, perturbation signal and blade operating temperature must be recorded at the same time. The selection of the recording speed of the recorder should be reasonable to ensure the measurement accuracy. 3.3.3.3 Telemetry method
Telemetry method refers to the method of using a sensor attached to the blade to transmit the vibration signal of the rotating blade through a transmitter fixed on the rotating part, which is received by a receiving antenna installed on the stationary part and then transmitted to the measuring instrument to measure the dynamic frequency. The telemetry test system is shown in Figure 5.
Official number processor
Yet
Transmission phase
Reception loss
Number fee
Figure 5 Block diagram of telemetry continental test system
Asking for the installation device
Special matching
When selecting a transmitter, the main technical indicators of the transmitter, such as signal-to-noise ratio, sensitivity, frequency response and wet drift, should meet the needs of dynamic measurement.
The transmitter should be tested before use, and its working performance must be stable. b.
c Correctly select the relationship between the transmitter carrier frequency and the length of the transmitting antenna to prevent the occurrence of dead zones. At the same time, the carrier frequency between the transmitters used should not be less than 1.5MHz.
d. The transmitter power supply can be battery power or induction power supply. When using battery power supply, the working environment temperature should be strictly controlled to ensure the normal operation of the battery.
88

JB/T6320—92
Supervisory transfer requires points
Flow R
Static
Circular speed device
tse||tt| |Feed generator
Fangtian 2
Enter tape record only
Figure 4 block diagram of the current concentration loop test system
No. processing point
The standard recommends two types of collecting rings. One is the kidney ring type collecting ring. The materials of slip ring and carbon ring should be correctly selected when using it, and the structural design should be reasonable. The other type is the mercury type collecting ring, which should be used strictly. Sealed to prevent mercury leakage. b. During the test, according to the test requirements, the excitation source can use piezoelectric body pieces, permanent magnets, AC and DC electromagnets, pressure gas, pressure liquid, etc.
c During the test, the rotation speed must be accurately measured, and the rotation speed signal, perturbation signal and blade operating temperature must be recorded at the same time. The recording speed of the recorder should be selected reasonably to ensure measurement accuracy. 3.3.3.3 Telemetry method
The telemetry method refers to using a sensor attached to the blade to transmit the vibration signal of the rotating blade through a transmitter fixed on the rotating part, and then receive it by a receiving antenna mounted on the stationary part. Then, it is passed to the measuring instrument to measure the dynamic frequency. The telemetry test system is shown in Figure 5. | |tt | Block diagram
Installer
Specialized equipment
When selecting a transmitter, the main technical indicators of the transmitter, such as signal-to-noise ratio, sensitivity, frequency response and wet drift, should meet the dynamic measurement requirements need.
The transmitter should be tested before use, and its working performance must be stable. b.
c Correctly choose the relationship between the transmitter carrier frequency and the length of the transmitting antenna to prevent dead zones. The carrier frequency between the transmitters used at the same time should not be less than 1.5MHz.||tt ||d. The transmitter power supply can be battery power or induction power. When using battery power, the working environment temperature should be strictly controlled to ensure normal operation of the battery.
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