ASTM D3377-00

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An American National Standard
Designation: D 3377 – 00
Standard Test Method for
1
Weight Loss of Solventless Varnishes
This standard is issued under the fixed designation D 3377; 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 3.1.1 varnish, n—electrical insulating, a liquid resin system
that is applied to and cured on electrical components providing
1.1 This test method covers the determination of the percent
electrical, mechanical, and environmental protection.
weight loss of cured solventless electrical varnishes when
3.1.1.1 Discussion—There are two types of electrical insu-
exposed to elevated temperatures for prescribed periods of
lating varnish: solvent-containing and solventless. The solvent-
time.
containing varnish is a solution, dispersion, or emulsion of a
1
1.2 Results of this test method are based on 6-mm ( ⁄4-in.)
polymer or mixture of polymers in a volatile, nonreactable
thick specimens and may not be applicable to specimens
liquid. The solventless type is a liquid resin system free of
appreciably thinner or thicker than 6 mm.
volatile, nonreactable solvents.
1.3 The values stated in SI units are to be regarded as the
3.1.2 For definitions of other terms relating to electrical
standard.
insulation, see Terminology D 1711.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Significance and Use
responsibility of the user of this standard to establish appro-
4.1 The amount and composition of by-products produced
priate safety and health practices and determine the applica-
by exposure of insulating varnishes to elevated temperatures
bility of regulatory limitations prior to use.
can possibly:
NOTE 1—This standard resembles IEC 60216–2 (1990–06) “Guide for
4.1.1 Deteriorate other insulations in the system,
the determination of thermal endurance properties of electrical insulating
4.1.2 Cause cracking of insulation due to pressure, buildup
materials. Part 2: Choice of test criteria” in a number of ways, but is not
in thick cross sections, or
consistently similar throughout. The data obtained using either standard
4.1.3 Corrode other parts in the assembly.
may be technically equivalent.
4.2 Amount and rate of weight loss may affect the thermal
2. Referenced Documents
rating of a varnish.
2.1 ASTM Standards:
5. Apparatus
2
D 1711 Terminology Relating to Electrical Insulation
5.1 Metal Mold, consisting of two flat sheets 300 by 300 by
D 5423 Specification for Forced-Convection Laboratory
1 1
3
6 mm (12 by 12 by ⁄4 in.) separated by 6.4-mm ( ⁄4-in.) thick
Ovens for Evaluation of Electrical Insulation
spacers along three sides. The spacers also seal the edges of the
2.2 IEC Standard:
mold and the assembly is held together with “C” clamps or
IEC 60216–2 Guide for the determination of thermal endur-
bolts. Aluminum or polished steel plates can be used.
ance properties of electrical insulating materials. Part 2:
4
5.2 Laboratory Balance, with accuracy of 6 1 mg.
Choice of test criteria
5.3 Forced-Convection Laboratory Oven, meeting require-
3. Terminology
ments of Specification D 5423, Type II for each test tempera-
ture.
3.1 Definitions:
1
5.4 Screening Platform, 6-mm ( ⁄4-in.) mesh, with 50-mm
(2-in.) legs.
1
This test method is under the jurisdiction of ASTM Committee D09 on
5.5 Mold Release.
Electrical and Electronic Insulating Materials and is direct responsibility of
Subcommittee D09.01 on Electrical Insulating Varnishes, Powders, and Encapsu-
NOTE 2—Fluorocarbon-type release agents are satisfactory.
lating Compounds.
5.6 Desiccator.
Current edition approved Nov. 10, 2000. Published January 2001. Originally
published as D 3377 – 75. Last previous edition D 3377 – 96.
2
Annual Book of ASTM Standards, Vol 10.01. 6. Procedure
3
Annual Book of ASTM Standards, Vol 10.02.
4 6.1 Apply a thin, uniform coating of release agent to the
Available from American National Standards Institute, 11 W. 42nd St., 13th
contact surfaces of the mold.
Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 3377
6.2 Assemble the mold, taking precautionary measures to
Hours—24 48 72 96 168
avoid leaks.
NOTE 4—If desired, exposure times can be extended.
6.3 Pour the sample into the open edge of the mold, using
6.15 After each test period, remove the specimens from the
care to avoid bubbles.
TABLE 1 Standard Deviation and Weight Loss
Weight Loss,% Standard Deviation
Hours at Temperature Oven Aging T
...