ASTM D295-99(2004)
(Test Method)Standard Test Methods for Varnished Cotton Fabrics Used for Electrical Insulation (Withdrawn 2009)
Standard Test Methods for Varnished Cotton Fabrics Used for Electrical Insulation (Withdrawn 2009)
SIGNIFICANCE AND USE
The thickness test is necessary to determine whether the material meets specified tolerances for thickness. In addition, thickness values are essential because of the importance of space factor in designing electrical equipment.
SCOPE
1.1 These test methods cover procedures for the testing of varnished cotton fabrics and varnished cotton fabric tapes (Note 0) to be used as electrical insulation and are directly applicable to both "straight-cut" and "bias-cut" materials, unless otherwise stated in the test method. Note 1—Methods of testing varnished glass fabrics and tapes are given in Test Methods D 902.
1.2 The procedures appear in the following order:ProceduresSectionsASTM Test MethodsBreaking Strength to ...ConditioningDielectric Breakdown Voltage to ...D 149Dielectric Breakdown Voltage Under Elongation to D 149Dissipation Factor and Permittivity to D 150ElongationResistance to Oil to to ...D 92Selection of Test Specimens...Tear Resistance to D 689Thickness to D 374Thread Count to ...Volume Resistance to D 257Weight to ...
1.3 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate.
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. For specific precautionary statements, see , , , and .Note 2
This standard resembles IEC 60394-2 in title only. The content is significantly different.
WITHDRAWN RATIONALE
These test methods cover procedures for the testing of varnished cotton fabrics and varnished cotton fabric tapes to be used as electrical insulation and are directly applicable to both “straight-cut” and “bias-cut” materials, unless otherwise stated in the test method.
Formerly under the jurisdiction of Committee D09 on Electrical and Electronic Insulating Materials, these test methods were withdrawn without replacement in 2010 because there is no indication that these test methods are being used in the industry.
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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.
An American National Standard
Designation:D295–99 (Reapproved 2004)
Standard Test Methods for
Varnished Cotton Fabrics Used for Electrical Insulation
This standard is issued under the fixed designation D295; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 2. Referenced Documents
1.1 These test methods cover procedures for the testing of 2.1 ASTM Standards:
varnished cotton fabrics and varnished cotton fabric tapes D92 Test Method for Flash and Fire Points by Cleveland
(Note 1) to be used as electrical insulation and are directly Open Cup Tester
applicable to both “straight-cut” and “bias-cut” materials, D149 Test Method for Dielectric Breakdown Voltage and
unless otherwise stated in the test method. Dielectric Strength of Solid Electrical Insulating Materials
at Commercial Power Frequencies
NOTE 1—Methodsoftestingvarnishedglassfabricsandtapesaregiven
D150 Test Methods for AC Loss Characteristics and Per-
in Test Methods D902.
mittivity (Dielectric Constant) of Solid Electrical Insula-
1.2 The procedures appear in the following order:
tion
ASTM Test
D257 Test Methods for DC Resistance or Conductance of
Procedures Sections Methods
Insulating Materials
Breaking Strength 20 to 27 .
Conditioning 5 .
D374 Test Methods for Thickness of Solid Electrical Insu-
Dielectric Breakdown Voltage 43 to 46 D149
lation
Dielectric Breakdown Voltage Under Elongation 47 to 53 D149
D689 Test Method for Internal Tearing Resistance of Paper
Dissipation Factor and Permittivity 54 to 60 D150
Elongation 35 to 42 .
D902 Test Methods for Flexible Resin-Coated Glass Fab-
Resistance to Oil 68 to 73 D92
rics and Glass Fabric Tapes Used for Electrical Insulation
Selection of Test Specimens 4 .
D1711 Terminology Relating to Electrical Insulation
Tear Resistance 28 to 34 D689
Thickness 6 to 10 D374
2.2 IEC Standard:
Thread Count 15 to 19 .
IEC 60394–2 Varnished Fabrics for Electrical Purposes —
Volume Resistance 61 to 67 D257
Part 2: Methods of Test
Weight 11 to 14 .
1.3 The values stated in inch-pound units are to be regarded
3. Terminology
as the standard. The metric equivalents of inch-pound units
3.1 Definitions: For definitions of terms used in these test
may be approximate.
methods refer to Terminology D1711.
1.4 This standard does not purport to address all of the
3.2 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the
3.2.1 weight—of varnished cloth and varnished cloth tapes,
responsibility of the user of this standard to establish appro-
the weight per unit area as determined in accordance with this
priate safety and health practices and determine the applica-
test method. It is usually expressed in pound per square yard
bility of regulatory limitations prior to use. For specific
for a specified nominal thickness.
precautionary statements, see 44.4, 51.1, 58.1, and 65.1.
3.2.2 threads per inch—of varnished cloths,thecountofthe
NOTE 2—This standard resembles IEC 60394–2 in title only. The number of warp and filling yarns present in the base cloth per
content is significantly different.
linear inch of width or length, respectively.
1 2
These test methods are under the jurisdiction of ASTM Committee D09 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Electrical and Electronic Insulating Materials and are the direct responsibility of contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Subcommittee D09.07 on Flexible and Rigid Insulating Materials. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Oct. 10, 1999. Published November 1999. Originally the ASTM website.
approved in 1928. Last previous edition approved in 1994 as D295 – 94. DOI: Available from American National Standards Institute, 11 W 42nd St.,New
10.1520/D0295-99R04. York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D295–99 (2004)
3.2.3 elongation—the amount of strain observed in a given TEST METHOD A: THICKNESS
length of varnished cloth or tape when subjected to prescribed
6. Significance and Use
loading conditions at prescribed atmospheric conditions. It is
expressed as a percentage of the initial length.
6.1 The thickness test is necessary to determine whether the
3.2.4 oil resistance—of varnished cloth or tape, the ability material meets specified tolerances for thickness. In addition,
thickness values are essential because of the importance of
of the varnish film to withstand the attack of oil without
excessive impairment of its physical and electrical character- space factor in designing electrical equipment.
istics when the varnished cloth or tape is immersed in a
7. Test Specimens
specified oil for a prescribed period of time at a given
temperature.
7.1 In the case of cloths or sheets, cut test specimens 1 in.
(25.4 mm) wide across the entire width. In the case of bias-cut
4. Selection of Test Specimens
cloth, exclude seams or jointed selvages from the area of test.
7.2 In the case of tapes or strips, remove specimens 36 in.
4.1 Select specimens for test from portions of material free
(910 mm) long from the sample of material selected in
from defects.
accordance with Section 4.
4.2 In the case of rolls of material other than those packed
in oil, remove the outer two layers of cloth or the outer six
8. Procedure
layers of tape and prepare test specimens from the remaining
8.1 Measure the thickness in accordance with Test Methods
material. In the case of oil-packed tape, remove the outer layer
D374, with the following modifications:
from each roll to be tested. In the case of sheets and tape strips,
8.1.1 Either Method B or Method C may be used but
remove the outer six layers of material and prepare test
Method C is to be used unless otherwise specified. Method A
specimens from that remaining.
shall not be used.
NOTE 3—In the case of bias-cut materials, exclude seams and jointed 8.1.2 In making thickness measurements, use only one layer
selvage from test areas.
of material.
NOTE 4—If it is desired to test seams and jointed selvages for breaking
8.1.3 In the case of cloths, take ten measurements equally
strength, prepare additional test specimens so that the seams or joints are
spaced across the width of the specimen. The thickness of the
in the center of the specimens.
cloth shall be the average of the ten measurements.
8.1.4 In the case of tapes, unless otherwise specified, take
5. Conditioning
ten measurements equally spaced along the length of each
5.1 Significance and Use—Because the physical and elec-
specimen. The thickness of the tape shall be the average of ten
trical properties of most fabrics change with variation of their
measurements.
moisture content, it is necessary to control this property at the
time of testing in order to attain reasonably good reproducibil- 9. Report
ity of test values. For example, when cotton fabric absorbs
9.1 Report the average, maximum, and minimum thickness
moisture it tends to swell and increase in dimensions.Also, the
in inches (or centimetres).
flexibility, elongation, and tensile strength of the material
normally increase with increased relative humidity, whereas,
10. Precision and Bias
conversely, the electrical properties are depreciated when the
10.1 Thistestmethodhasbeeninuseformanyyears,butno
material is subjected to these conditions. The time of exposure
information has been presented to ASTM upon which to base
to the conditioned atmosphere must be long enough to permit
a statement of precision. No activity has been planned to
the moisture content of the test specimen to reach a relatively
develop such information.
stable value. If the fabric is untreated, a few hours exposure is
10.2 This test method has no bias because the value for
sufficient. Treated fabrics like varnished cloth require appre-
thickness is determined solely in terms of this test method
ciably longer time.
itself.
5.2 Where it is desired to test in a controlled atmosphere,
condition the test specimens for 48 h in the Standard Labora-
TEST METHOD B: WEIGHT
tory Atmosphere of 50 6 2 % relative humidity at 23 61°C
(73.4 6 1.8 °F). If a conditioning cabinet or chamber is used, 11. Significance and Use
subject the specimens to test immediately upon withdrawal
11.1 Weight values are useful for estimating weight in
from the cabinet or chamber, unless otherwise specified.
designing electrical equipment containing a constituent part of
5.3 If it is desired to test the material in the condition as varnished cloth or tape.
received by the purchaser, allow the packages containing the
12. Procedure
rolls of material from which the specimens are to be taken to
reach room temperature before opening. Open the packages,
12.1 Prepare either square or rectangular specimens of
remove the roll and immediately prepare such test specimens
sufficient size to weigh not less than 0.18 oz (5 g). Accurately
as required, unless otherwise specified.
weigh on an analytical balance. Measure the length and width
5.4 In the case of dispute, the procedure described in 5.2 dimensions with sufficient precision to be able to compute the
shall be the referee method. area within 0.3 %. Compute the weight per unit area.
D295–99 (2004)
13. Report 19.2 This test method has no bias because the value for
thread count is determined solely in terms of this test method
13.1 Report a description of the material and the weight in
itself.
pounds per square yard or kilograms per square metre.
TEST METHOD D: BREAKING STRENGTH
14. Precision and Bias
14.1 Thistestmethodhasbeeninuseformanyyears,butno
20. Significance and Use
information has been presented to ASTM upon which to base
20.1 The breaking strength of finished cloth and tape is of
a statement of precision. No activity has been planned to
importance as a measure of its ability to withstand reasonable
develop such information.
pulling without failure while being applied.
14.2 This test method has no bias because the value for
weight per unit area is determined solely in terms of this test
21. Apparatus
method itself.
21.1 Testing machines of the dead-weight pendulum or of
the constant-rate-of-elongation types shall be used, the latter
TEST METHOD C: THREAD COUNT
being preferred.
21.2 The machine shall be graduated to read 0.5 kg or 1 lb,
15. Terminology
or less per scale division for testing specimens breaking at 50
15.1 Definitions of Terms Specific to This Standard:
lb (22.7 kg) or over, and to 0.25 kg, or 0.5 lb, or less for testing
15.1.1 threads per inch—of varnished cloths, the count of
specimens breaking under 50 lb.
the number of warp and filling yarns present in the base cloth
per linear inch of width or length, respectively.
22. Test Specimens
22.1 Cut test specimens 1 in. (25.4 mm) in width and not
16. Significance and Use
less than 12 in. (305 mm) in length from full-width cloth or
16.1 Thread count, together with the weight and width of
from tapes over 1 in. (25.4 mm) in width. In the case of tapes
thecloth,isacceptedasthecommonmeansfordesignatingand
having a nominal width of 1 in. (25.4 mm) or less, prepare test
identifying cloth constructions.
specimensnotlessthan12in.(305mm)longusingtheoriginal
16.2 Certain of the physical and electrical properties of
width.
wovenfabricsaredependentonthreadcount.Thatis,assuming
NOTE 7—If it is desired to test the seams or jointed selvages of bias-cut
the same size of yarn, an increase in thread count increases the
materials for breaking strength, mount specimens obtained as described in
weight, breaking strength, and density of the cloth. Also, the
Note 4,(4.2) in the testing machine so that the seams or jointed selvages
dielectric breakdown voltage and the dissipation factor of the
are midway between the two jaws.
varnished fabric may be changed by altering the thread count
of the cloth. 23. Number of Specimens
23.1 In the case of straight-cut cloths, cut five specimens in
17. Procedure
the direction of the warp threads and five in the direction of the
17.1 Determine separately the warp and filling threads per filling threads from samples selected in accordance with 4.1
and 4.2.
inch of cloth by counting in a space of not less than 1 in. (25.4
mm) in at least five different places on the specimen. The 23.2 In the case of bias-cut cloths, cut five specimens in the
direction of the length from samples selected in accordance
average of the five determinations shall be the thread count.
with 4.1 and 4.2.
23.3 In the case of tapes, cut five specimens from each roll
18. Report
selected in accordance with 4.1 and 4.2.
18.1 Report the warp count and the filling count separately
as threads per inch (or millimetre).
24. Conditioning
NOTE 5—The warp threads in straight-cut materials are the threads that
24.1 Condition specimens in accordance with Section 5.
are parallel with the length or machine-direction dimension, while in
bias-cut materials the warp threads are parallel with the seams or jointed
25. Procedure
selvages.
NOTE 6—Beforecountingblackvarnishedmaterialsitwillbenecessary
25.1 Adjust the clearance distance between jaws to be 6 in.
to remove the varnish film with a knife blade or other suitable instrument.
(150 mm).
Liquid varnish removers are unsuitable for this purpose as they may cause
25.2 Select the rate of travel of the movable jaw to be
aswellingofthefibersandashrinkageofclothwithaconsequentincrease
constant and preferably 12 in. (305 mm)/min, but it may be
in threads per inch count; therefore, the films must be removed mechani-
within the limits of 11 and 13 in. (280 and 330 mm)/min,
cally.
provided it is constant.
19. Precision and Bias
25.3 Reject all readings obtained when the specimens break
at or in the jaws.
19.1 Thistestmethodhasbeeninuseformanyyears,butno
information has been presented to ASTM upon which to base
26. Report
a statement of precision. No activity has been planned to
develop such information. 26.1 Report the following information:
D295–99 (2004)
26.1.1 The average, maximum, and minimum breaking the jaws. Obtain warp tears by tearing across warp direction
loads in kilograms or pounds, together with the width of the threads and filler tears by tearing across filler direction threads.
specimens and the nominal thickness, and
NOTE 9—Discard test values where the end of the tear doe
...
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