JB/T 8689-2014 PDF in English
JB/T 8689-2014 (JB/T8689-2014, JBT 8689-2014, JBT8689-2014)
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Fan vibration detection and its limited value
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| JB/T 8689-1998 | English | 279 |
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Fan vibration detection and its limited value
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Standards related to (historical): JB/T 8689-2014
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JB/T 8689-2014: PDF in English (JBT 8689-2014) JB/T 8689-2014
MECHANICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 23.120
J 72
Registration number: 47249-2014
Replacing JB/T 8689-1998
Fan vibration detection and its limited value
ISSUED ON: JULY 09, 2014
IMPLEMENTED ON: NOVEMBER 01, 2014
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Terms and definitions ... 4
3 Requirements ... 6
3.1 Measurement parameters and their limits ... 6
3.2 Measurement location ... 6
3.3 Measuring instruments ... 8
3.4 Installation of the tested fan ... 8
3.5 Operating conditions of the tested fan ... 9
Appendix A (Informative) Limits of vibration velocity and vibration displacement
... 10
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces JB/T 8689-1998 “Fan vibration detection and its limited
value”. As compared with JB/T 8689-1998, the main technical changes are as
follows:
- In the foreword, ADD the release of each version of this standard;
- In the scope, MODIFY the descriptions;
- REVISE the Appendix A (Suggestive) in 3.3.1 to Appendix A (Informative).
- REVISE the Appendix A (Suggestive) to Appendix A (Informative).
This standard was proposed by the China Machinery Industry Federation.
This standard shall be under the jurisdiction of the National Fan Standardization
Technical Committee (SAC/TC 187).
Drafting organizations of this standard: Shenyang Blower Research Institute
(Co., Ltd.), Chongqing General Industrial (Group) Co., Ltd., Shangyu Fan Co.,
Ltd., Zhejiang Yilida Fan Co., Ltd., Shanghai General Fan Co., Ltd.
The main drafters of this standard: Chen Zhongcai, Chen Fengyi, Zheng Hua,
Liao Yulong, Yu Haishui, Zhang Qizhong, Gong Xinglong.
This standard replaces the standard previously issued as follows:
- JB/TQ 334-1984, JB/TQ 334-1987, JB/T 8689-1998.
Fan vibration detection and its limited value
1 Scope
This standard specifies the vibration limit of the operation of the fan, the
measurement part of the vibration of the fan, the requirements of measuring
instrument, the installation of the tested product, the operating conditions during
the measurement.
This standard is applicable to the exit-factory inspection and type test of the
centrifugal, axial and mixed flow fans as well as the acceptance of on-site
vibration indicators.
2 Terms and definitions
The following terms and definitions apply to this document.
2.1
Root-mean-square value of vibration velocity
The rms value of the vibration velocity, which is also called the effective value
of the vibration velocity.
For periodic vibration, it refers to the square root of the average value of the
instantaneous value of the vibration velocity in a vibration period. Its
mathematical expression is as follows:
Where:
vrms - The rms value of vibration velocity (effective value), in millimeters per
second (mm/s);
T - The vibration period, in seconds (s);
v(t) - The function of the vibration velocity as a function of time t, in
millimeters per second (mm/s);
t - The independent variable of time, in seconds (s).
For sinusoidal vibration at a single frequency, v(t) = vcoswt, the rms value of
the vibration velocity as obtained by the above formula is:
Where:
v - Single peak of vibration velocity, in millimeters per second (mm/s).
Where:
X - The single peak value of vibration displacement, in millimeters (mm);
w - The angular frequency, in radians per second (rad/s).
2.2
Periodic vibration
The vibration whose vibration waveform repeats once per a time period P.
2.3
Rigid support
After the fan is installed, when the basic natural frequency of the “fan-support
system” is higher than the main working frequency of the fan, it is called rigid
support.
Note: Generally, fan is directly fixed and connected to the rigid foundation.
2.4
Flexible support
After the fan is installed, when the basic natural frequency of the “fan-support
system” is lower than the main working frequency of the fan, it is called
flexible support.
Note: Under special conditions, the fan is connected to the foundation
through the vibration isolator.
3.5 Operating conditions of the tested fan
3.5.1 The fan shall be operated at a stable rated speed and rated conditions. If
the fan has multiple rated speeds and rated conditions, it shall respectively
measure the vibrations under various rated conditions. Take the maximum
measured value to represent the vibration value of this fan. Meanwhile indicate
the operating conditions at the time of measurement.
3.5.2 Due to the objective conditions, if the rated speed and the rated condition
of the fan cannot be achieved at the same time during the test, it shall be as
close as possible to the rated conditions at the rated speed, measure the
vibration value and record the operating conditions during the measurement.
3.5.3 If the fan adopts the variable speed regulator to regulate the range of use,
it shall, within the speed regulating range as specified for the fan, respectively
measure the vibration value at 3 speeds: high, medium, low. At each speed, it
shall be as close as possible to the working conditions. Take the maximum
measured value to represent the vibration value of the fan. Meanwhile indicate
the operating conditions at the time of measurement.
3.5.4 If the fan cannot meet the actual hot-state running conditions during test,
it may, under the cold-state, use the conditions as close to the rated working
conditions as possible as allowed for the motor. Meanwhile indicate the
operating conditions at the time of measurement.
3.5.5 The difference between the vibration value of the fan when it is running
and when it is not running shall be more than 3 times the vibration value of the
fan when it is not running. Otherwise, it is considered that the tested fan has an
external vibration environment, in this case it shall take measures to avoid
external influences.
3.5.6 The temperature, humidity, magnetic field, corrosion characteristics, etc.
around the fan shall meet the requirements for the use of the instrument.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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