GB/T 12779-1991 Methods for measuring and rating the vibration of reciprocating machines GB/T12779-1991 Standard download decompression password: www.bzxz.net

UDC 621-12 : 620. 178. 5
National Standard of the People's Republic of China
GB/T 12779— 91
Method of neasurement and evaluation of mechanical vibration for reciprocating machines1991 - 03-26 Issued
State Administration of Technical Supervision
Implementation on 1992-01-01
National Standard of the People's Republic of China
Method of measurement and evalation of mcchanlcalvibraltion for recipracatlng machines1 Main content and scope of application
GB/R 12779-91
This standard specifies the method for measurement and evaluation of the overall vibration of reciprocating piston machines. This standard applies to the vibration measurement and assessment of reciprocating piston machines such as marine main and auxiliary engines, diesel engines in diesel generator sets, locomotive diesel engines, reciprocating air compressors, etc. with a speed higher than 300t/min. This standard does not apply to reciprocating machines such as punching machines, sawing machines, textile buttons, and testing machines. The machines can be installed together with the elastic supports that match them for assessment. 2 Measurement scale
2.1 Measurement scale
Take the effective value of the vibration velocity as a step scale, defined as: ()
In the formula: 3ma-
Perturbation velocity effective, mm/s:
()—Time period of vibration velocity periodicity, mm/sT—Period of vibration velocity change according to time, 5. If (t) is composed of several known simple harmonic components, the following formula can be used for calculation. When the effective value of the vibration velocity of the running component is m2 (=1,2) me ++ thy + ++m.
When the vibration peak of the component (i-1,2n) is given in the appendix; word +w
2.2 Evaluation basis
Represents the recording standard of the overall vibration of the Kai device and takes the "equivalent vibration intensity", which is defined as follows: Where; 5 equivalent vibration intensity, mm/s;
h+1y +g --
respectively are the effective values ​​of vibration velocities measured in three perpendicular directions, mm/s; respectively are the number of measuring points in the three directions
W+,Ny+N2 -
Approved by the State Administration of Technical Supervision on March 26, 1991 (2)
Implemented on January 1, 1992
3 Measuring system and instruments
3.tMeasuring and recording system
GB/T12779—91
3.1.1 The components of the measuring system are shown in the figure below; sensors
It is allowed to use other instrument combinations that ensure measurement accuracy, amplifiers
with oscilloscopes
3.1.2 The measurement is the effective value of the vibration velocity signal within a certain frequency range. The lower limit of the measurement frequency range should include the machine's first-order vibration signal.
For machines with a rotation speed of more than 600/mm, the frequency range is 101000Hz. For machines with a rotation speed of 300~600z/min, the rated frequency range is 3~1000Hz.
3.1.3 When the frequency range is (0~1000Hz), the relative sensitivity of the measurement system to vibration velocity shall meet the requirements of Table 1. Table 1 Rated value Relative sensitivity Minimum value Maximum value 3.1.4 When the frequency range is 3~-1000Hz, in addition to meeting the requirements of Table 1, the relative sensitivity of the measurement system to vibration velocity shall be 10 The relative sensitivity below Hz shall also meet the requirements of Table 2. Table?
Rated value
Relative sensitivity variation
Minimum value
Maximum value
3.1.5 Principles for selecting the measuring range of the indicating meter: the minimum vibration level shall not be less than 30% of the full scale of the indicating device, and the minimum inter-indicator constant shall be set at 1$.
3.2 Sensor
3.2.1 The sensor shall be installed firmly and reliably at the measured point, and shall not move during the entire measurement process. The connection system shall be within the measuring frequency range of 2
GB/I ​​12779 .91
The range of the sensor should ensure the correct transmission of the vibration signal. 32.2 The sensor should work normally under the permitted working environment (such as temperature, humidity, magnetic field, oil pollution, salt, etc.). 32.3 The sensor should be calibrated in time after the positive state (such as overcharge, overheating, water, oil immersion, etc.), and it can be used again only when it is confirmed that the original performance is not reduced.
3.2.4 The sensor should have a survivability, and the directional sensitivity should not exceed 10% of the sensitivity of the main measurement direction. That is, the horizontal extinction degree is required to be less than 10%.
3.3 Connecting wires
3.3.1 The wire selection should match the test system. 3.3.2 The wire should be fixed and there should be no relative movement between it and the object being tested. 3.4 Indicator and recording device
3.4.1 Direct reading indicator device should be able to give the effective value of the speed (pointer type, digital type). 3.4.2 The test system can be equipped with a recording device, and the recording device can be selected as a printer. printer, tape recorder or optical oscilloscope. When recording waveforms, the effective perturbation velocity can be calculated according to formula (2) and formula (3). 4 Measurement point location and measurement direction
4.1 The measurement point location should be selected at the place where the vibration energy is transmitted to the vibration base or other parts of the system: the front and rear ends of the machine, the top and bottom, at least 4 points. If the machine size is large and additional points are required, they should be added in groups on behalf of the top and bottom of the machine. When elastic support is used, the bottom measurement point should be selected above the elastic support and the support part. 42 The measurement point should be selected at the part of the machine that can represent the vibration of the machine. The part that generates local vibration should not be arranged. The measurement point number is indicated by 1.2.3.
43 The measurement base direction is selected in two mutually perpendicular directions, that is, the first direction is measured in the direction of the machine rotation axis, and the second direction is horizontal. Note that it is perpendicular to the machine rotation axis; the third direction is perpendicular to the plane formed by the above two directions, and is represented by (, 3, and 43 coordinates respectively. 5 Measurement conditions
5.1 The machine under test is in normal installation state
Measurement can be carried out only when the machine reaches normal reading state. 5.3 The measurement should be carried out under the typical use of the device. 5.4 The test environment 1 should be free from strong external interference. 6 Measurement report
The measurement report shall include: the measured object and the distribution of measuring points, attached drawings, measuring environment, measuring instruments, original data and equivalent vibration intensity calculation method.bzxz.net
7 Rating of equivalent vibration intensity
7.1 The vibration intensity is graded from 0.071 mm/s. at a ratio of 1:1.6 (minimum 4 dB). See Table 3, \Grading range limit value* Table 3 shows the level of vibration intensity. "Vibration intensity range" indicates the range of vibration intensity of that level. Table 3 Grading range limit value
Vibration intensity range
n. 07:-0. 112
-0. [12--0.18
-0. 18~0. 28
Grading range limit value
GB/T 1277991
Continued Table 3
Report confusion diagram
>>0. 28 -~ 0. 45
0. 45~0. 71
0. 71 ~1. 12
>1.12~1.8
>1, R~2. 8
>2. B~4, 5
1. 5 ~7.1
>7. J ~ 11. 2
>28~45
7.2 Classification of vibration quality
Based on the measured vibration intensity value, the vibration quality of the machine end is divided into four levels, defined as: Class A
Tolerable
Not allowed
The upper limit of the limit is specified for Class A, Class D only specifies the lower limit, and Classes B and C are two levels of vibration intensity classification range, see Table A (reference).
GB/1 12779-91
Appendix A
(reference)
A1 In order to illustrate how to use the method proposed in this standard, a simple example of a typical reciprocating machine is given below for reference when formulating the limit values ​​of the equivalent perturbation intensity level of the machine. Table A1 shows the current standards formulated for the method proposed in this standard as an example, but does not include the limits of vibration ratings for all types of reciprocating machines. Different machines should be determined according to their specific structures and working conditions. The vibration characteristics of the foundation or stand used for the machine have a significant impact on the vibration intensity of the machine. This is especially important when the machine is installed on a carrier (such as a ship, locomotive, etc.). When determining the limit values ​​of the equivalent vibration intensity, attention must be paid to it.
Intensity classification
Additional instructions:
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