ASTM D1389-97a
(Test Method)Standard Test Method for Proof-Voltage Testing of Thin Solid Electrical Insulating Materials
Standard Test Method for Proof-Voltage Testing of Thin Solid Electrical Insulating Materials
SCOPE
1.1 This test method covers a general procedure for proof-voltage testing of thin solid electrical insulating materials at commercial power frequencies. It is intended to apply principally to flat materials but is applicable, with modification, to any form that permits continuously passing the material between suitable electrodes.
1.2 On extremely thin materials (usually less than 0.05 mm (0.002 in.)) the test results may be influenced more by mechanical damage caused by conditions of test than by dielectric defects. Consequently, this test method is not recommended for use with extremely thin materials, unless prior determination has established that the test results are not influenced by mechanical damage.
1.3 While the equipment and procedures described in this test method relate specifically to tests made with power frequency ac voltages, similar equipment and procedures are used for proof-voltage tests using dc voltages. To the extent that it applies to dc tests, this test method can serve as a guide for persons making such tests. However, only tests made with power frequency ac voltages can be said to be in accordance with this test method.
1.4 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 hazard statements, see Section 7.
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An American National Standard
Designation: D 1389 – 97a
Standard Test Method for
Proof-Voltage Testing of Thin Solid Electrical Insulating
Materials
This standard is issued under the fixed designation D 1389; 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 D 149 Test Method for Dielectric Breakdown Voltage and
Dielectric Strength of Solid Electrical Insulating Materials
1.1 This test method covers a general procedure for proof-
at Commercial Power Frequencies
voltage testing of thin solid electrical insulating materials at
commercial power frequencies. It is intended to apply princi-
3. Terminology
pally to flat materials but is applicable, with modification, to
3.1 Definitions:
any form that permits continuously passing the material
2,3 3.1.1 proof voltage test, n—a test during which a specified
between suitable electrodes.
voltage is applied to a specimen to determine whether break-
1.2 On extremely thin materials (usually less than 0.05 mm
down will occur at that voltage. Fixed electrodes may be used,
(0.002 in.)) the test results may be influenced more by
in which case the voltage is held for a specified time; or large
mechanical damage caused by conditions of test than by
area specimens may pass between roller, brush, or blade
dielectric defects. Consequently, this test method is not recom-
electrodes, in which case the speed is specified.
mended for use with extremely thin materials, unless prior
determination has established that the test results are not
4. Summary of Test Method
influenced by mechanical damage.
4.1 In this test method, sheet insulating material is passed at
1.3 While the equipment and procedures described in this
a specified speed between roller electrodes with a specified ac
test method relate specifically to tests made with power
voltage applied, so that all, or nearly all, of the area of the
frequency ac voltages, similar equipment and procedures are
material is subjected to the specified voltage. The number of
used for proof-voltage tests using dc voltages. To the extent
electrical breakdowns and their locations are determined.
that it applies to dc tests, this test method can serve as a guide
4.2 The applied proof voltage may be selected as a percent-
for persons making such tests. However, only tests made with
age of the dielectric breakdown voltage, as determined in
power frequency ac voltages can be said to be in accordance
accordance with Test Method D 149, or as a multiple of the
with this test method.
breakdown voltage for an air gap of equal thickness.
1.4 This standard does not purport to address all of the
4.3 Unless the material being tested is known to have high
safety concerns, if any, associated with its use. It is the
resistance to partial discharges, the proof voltage is ordinarily
responsibility of the user of this standard to establish appro-
selected to be below the visible corona level. If it is necessary
priate safety and health practices and determine the applica-
to test at a voltage at which visible corona will be present, the
bility of regulatory limitations prior to use. For specific hazard
degradation of the material resulting from exposure to corona
statements, see Section 7.
should be weighed against the advantages of testing at the high
2. Referenced Documents voltage level.
4.4 Two values for the rate of movement of the material
2.1 ASTM Standards:
between the electrodes are given to facilitate handling of
different types of materials. The results obtained with the
This test method is under the jurisdiction of ASTM Committee D-9 on different speeds are not equivalent.
Electrical and Electronic Insulating Materials and is the direct responsibility of
Subcommittee D09.12 on Electrical Tests.
5. Significance and Use
Current edition approved Sept. 10, 1997. Published January 1998. Originally
5.1 Occasional dielectric defects may be found in commer-
published as D 1389 – 56 T. Last previous edition D 1389 – 97.
Bartnikas, R., Chapter 3, “High Voltage Measurements,” Electrical Properties cially available and acceptable thin electric insulating materi-
of Solid Insulating Materials, Measurement Techniques, Vol. IIB, Engineering
als. More often than not, these materials are used in multiple
Dielectrics, R. Bartnikas, Editor, ASTM STP 926, ASTM, Philadelphia, 1987.
layers. The probability that occasional dielectric weak spots
Nelson, J. K., Chapter 5, “Dielectric Breakdown of Solids,” Electrical
Properties of Solid Insulating Materials: Molecular Structure and Electrical
Behavior, Vol. IIA, Engineering Dielectrics, R. Bartnikas and R. M. Eichorn,
Editors, ASTM STP 783, ASTM, Philadelphia, 1983. Annual Book of ASTM Standards, Vol 10.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 1389
will coincide from layer to layer is very small but increases method of measurement. As related to this specific test method,
with the frequency of occurrence of these defects. The proof- some design details that are useful are described in 6.2-6.5, and
voltage test serves to indicate the frequency of occurrence of in Fig. 1.
dielectric defects and facilitates the isolation of areas where the
6.2 System Considerations—Departure from a sinusoidal
defects are excessive.
wave form may arise either at the voltage source or in the load
5.2 Some uses of thin electrical insulating materials require
circuit. Excessive distortion due to load current can usually be
the complete absence of any dielectric defects. The proof-
avoided if the overall impedance drop through the apparatus at
voltage test serves to locate dielectric defects, making possible
rated current and voltage is less than 10 % of the rated voltage,
repair or replacement of the area involved as may be desirable.
and provided the ratio of test voltage to rated voltage is not too
5.3 In the absence of detected faults, this test method is
small; the lower limit of this ratio can be determined by test.
nondestructive to the material being evaluated, except as
The apparatus should be of such size and design that fault
discussed in 1.2 and 4.3.
currents at breakdown produce visually observable ruptures.
5.4 A critical part of the apparatus and procedure is the
The magnitude of the fault current required will depend on the
sensitivity and speed of response of the fault detection device,
material being tested.
usually a circuit breaker. The results obtained using different
6.3 Transformer—The desired test voltage is readily ob-
sets of apparatus may differ greatly, depending upon the
tained from a step-up transformer energized from an adjustable
characteristics of this component.
voltage source. The transformer must be of such size and
5.5 It is essential that the fault detector respond only to fault
design that its continuous duty rating is consistent with the
currents, and that fault currents above a predefined value
requirements as specified in 6.1. Standard 5 kVA or larger
should always make the fault detector respond. The design,
distribution transformers 14400/13200 to 120/240 or 240/480
adjustment, and operation of the apparatus should be such as to
V with less than 5 % impedance drop are readily available and
avoid both erroneous functioning and erroneous nonfunction-
their use is suggested.
ing of the detector resulting from charging currents, magnetiz-
6.4 Fault Detector—Fault detection shall be provided by an
ing currents, corona currents, imbalance of circuit impedences,
automatic circuit-breaking device with non-automatic reset. In
or component malfunction.
order to provide detection of the smallest defects, to prevent
5.6 The proof-voltage test may be used as a manufacturing
pitting of the electrodes, and to provide maximum protection of
control test and as an acceptance test to guarantee a minimum
the other electrical elements, the fault detector should be as
level of dielectric defects.
sensitive and as fast-acting as possible. On the other hand, the
5.7 If this test method is used as an acceptance test, take
task of visually locating dielectric punctures in some types of
care that the factors discussed in 5.4 and 5.5 have been
materials may be difficult if the fault current is interrupted too
considered, and, if more than one set of apparatus is to be used,
quickly. Therefore, the current setting and the response time of
that comparable results are obtained from them.
the fault detector must be related to the material being tested.
CR ,CR , and CR , shown in Fig. 1, may be separate fixed
1 2 3
6. Apparatus
devices having differing characteristics, or may be a single
6.1 General Requirements—The test voltage must conform device which can be set to different current and time values as
to the requirements of Test Method D 149, relative to its needed. The circuit breaker (CB) of Fig. 1 should have a
variation from nominal value, wave-s
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