ASTM D6786-07
(Test Method)Standard Test Method for Particle Count in Mineral Insulating Oil Using Automatic Optical Particle Counters
Standard Test Method for Particle Count in Mineral Insulating Oil Using Automatic Optical Particle Counters
SIGNIFICANCE AND USE
Particles in insulating oil can have a detrimental effect on the dielectric properties of the fluid, depending on the size, concentration, and nature of the particles. The source of these particles can be external contaminants, oil degradation by-products, or internal materials such as metals, carbon, or cellulose fibers.
Particle counts provide a general degree of contamination level and may be useful in accessing the condition of specific types of electrical equipment. Particle counts can also be used to determine filtering effectiveness when processing oil.
If more specific knowledge of the nature of the particles is needed, other tests such as metals analysis or fiber identification and counting must be performed.
SCOPE
1.1 This test method covers the determination of particle concentration and particle size distribution in mineral insulating oil. It is suitable for testing oils having a viscosity of 6 to 20 cSt at 40°C. The test method is specific to liquid automatic particle analyzers that use the light extinction principle.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D6786–07
Standard Test Method for
Particle Count in Mineral Insulating Oil Using Automatic
1
Optical Particle Counters
This standard is issued under the fixed designation D 6786; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 concentration limit—a direct function of coincidence
and electronic saturation.The concentration limit of the system
1.1 This test method covers the determination of particle
is determined by the maximum acceptable concentration of
concentration and particle size distribution in mineral insulat-
particles in the given sample and is supplied by the instrument
ing oil. It is suitable for testing oils having a viscosity of 6 to
manufacturer.
20 cSt at 40°C. The test method is specific to liquid automatic
3.1.3 electronic saturation level—particle concentration at
particle analyzers that use the light extinction principle.
whichtheelectroniccircuitryoftheanalyzerceasestofunction
1.2 This standard does not purport to address all of the
properly due to excessive counting rates.
safety concerns, if any, associated with its use. It is the
3.1.4 light extinction—the reduction in intensity of a light
responsibility of the user of this standard to establish appro-
beam passing through the sensing zone of a particle analyzer,
priate safety and health practices and determine the applica-
caused by the absorption and/or scattering of the light by
bility of regulatory limitations prior to use.
particles. Synonyms: light obscuration, light interruption, light
2. Referenced Documents
blockage.
2
2.1 ASTM Standards:
4. Summary of Test Method
D 923 Practices for Sampling Electrical Insulating Liquids
4.1 Samples are taken in particle-clean bottles that are
2.2 ISO Standards:
suitable for particle analysis. The sample bottle is agitated to
4406:1999 Hydraulic Fluid Power—Fluids—Method for
3
redistribute particles in the oil, then the oil is placed in an
Coding the Level of Contamination by Solid Particles
automatic particle counter, where the number of particles and
11171:1999 Hydraulic Fluid Power—Calibration of Auto-
3
their size distribution are determined by the light extinction
matic Particle Counters for Liquids
principle.
3. Terminology 4.2 As particles pass through the sensing zone of the
instrument, the quantity of light reaching the detector is
3.1 Definitions:
obscured. This signal is translated to an equivalent projected
3.1.1 coincidence—the presence of more than one particle
area diameter based on calibration with a NIST-traceable fluid
in the sensing zone of a particle analyzer at the same time,
(ISO Medium Test Dust suspension).
causing mis-sizing and mis-counting of the particle present.
The coincidence limit of the counter is determined by the
5. Significance and Use
maximum acceptable concentration of particles in the sensing
5.1 Particles in insulating oil can have a detrimental effect
zone and is supplied by the instrument manufacturer.
on the dielectric properties of the fluid, depending on the size,
concentration, and nature of the particles. The source of these
1
This test method is under the jurisdiction of ASTM Committee D27 on
particles can be external contaminants, oil degradation by-
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
products, or internal materials such as metals, carbon, or
mittee D27.07 on Physical Test.
cellulose fibers.
Current edition approved Dec. 1, 2007. Published January 2008. Originally
5.2 Particle counts provide a general degree of contamina-
approved in 2002. Last previous edition approved in 2002 as D 6786–02.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tion level and may be useful in accessing the condition of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
specific types of electrical equipment. Particle counts can also
Standards volume information, refer to the standard’s Document Summary page on
be used to determine filtering effectiveness when processing
the ASTM website.
3
Available from American National Standards Institute, 11 West 42nd Street, oil.
New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D6786–07
5.3 If more specific knowledge of the nature of the particles 9. Sampling
is needed, other tests such as metals analysis or fiber identifi-
9.1 Refer to Practice D 923 for precautions for sampling
cation and counting must be performed.
from energized electrical equipment.
9.2 P
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D6786–02 Designation:D6786–07
Standard Test Method for
Particle Count in Mineral Insulating Oil Using Automatic
1
Optical Particle Counters
This standard is issued under the fixed designation D 6786; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of particle concentration and particle size distribution in mineral insulating oil.
It is suitable for testing oils having a viscosity of 6 to 20 cSt at 40°C. The test method is specific to liquid automatic particle
analyzers that use the light extinction principle.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
D 923 Practices for Sampling Electrical Insulating Liquids
2.2 ISO Standards:
3
4406:1999 Hydraulic Fluid Power—Fluids—Method for Coding the Level of Contamination by Solid Particles
3
11171:1999 Hydraulic Fluid Power—Calibration of Automatic Particle Counters for Liquids
3. Terminology
3.1 Definitions:
3.1.1 coincidence—the presence of more than one particle in the sensing zone of a particle analyzer at the same time, causing
mis-sizingandmis-countingoftheparticlepresent.Thecoincidencelimitofthecounterisdeterminedbythemaximumacceptable
concentration of particles in the sensing zone and is supplied by the instrument manufacturer.
3.1.2 concentration limit—a direct function of coincidence and electronic saturation. The concentration limit of the system is
determined by the maximum acceptable concentration of particles in the given sample and is supplied by the instrument
manufacturer.
3.1.3 electronic saturation level—particle concentration at which the electronic circuitry of the analyzer ceases to function
properly due to excessive counting rates.
3.1.4 light extinction—the reduction in intensity of a light beam passing through the sensing zone of a particle analyzer, caused
by the absorption and/or scattering of the light by particles. Synonyms: light obscuration, light interruption, light blockage.
4. Summary of Test Method
4.1 Samples are taken in particle-clean bottles that are dedicated tosuitable for particle analysis. The sample bottle is agitated
to redistribute particles in the oil, then immediatelythe oil is placed in an automatic particle counter, where the number of particles
and their size distribution are determined by the light extinction principle.
4.2 As particles pass through the sensing zone of the instrument, the quantity of light reaching the detector is obscured. This
signal is translated to an equivalent projected area diameter based on calibration with a NIST-traceable fluid (ISO Medium Test
Dust suspension).
1
This test method is under the jurisdiction ofASTM Committee D27 on Electrical Insulating Liquids and Gases and is the direct responsibility of Subcommittee D27.07
on Physical Tests.
Current edition approved April 10, 2002. Published June 2002.
1
This test method is under the jurisdiction ofASTM Committee D27 on Electrical Insulating Liquids and Gases and is the direct responsibility of Subcommittee D27.07
on Physical Test.
Current edition approved Dec. 1, 2007. Published January 2008. Originally approved in 2002. Last previous edition approved in 2002 as D 6786–02.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 10.03.volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from American National Standards Institute, 11 West 42nd Street, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D6786–07
5. Significance and Use
5.1 Particles in insulating oil can have a detrimental effect on the dielectric properties of the fluid, depending on the size,
concentration, and nature of the particles. The source of these particles can be external contaminants, oil degradation by-products,
or internal materials such as me
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.