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 1) 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 D902.
1.2 The procedures appear in the following order:
| Procedures | Sections | ASTM Test Methods |
| Breaking Strength | 20 to 27 | ... |
| Conditioning Dielectric Breakdown Voltage | 5 43 to 46 | ... D149 |
| Dielectric Breakdown Voltage Under Elongation | 47 to 53 | D149 |
| Dissipation Factor and Permittivity | 54 to 60 | D150 |
| Elongation Resistance to Oil | 35 to 42 68 to 73 | ... D92 |
| Selection of Test Specimens | 4 | ... |
| Tear Resistance | 28 to 34 | D689 |
| Thickness | 6 to 10 | D374 |
| Thread Count | 15 to 19 | ... |
| Volume Resistance | 61 to 67 | D257 |
| Weight | 11 to 14 | ... |
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.
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 precautionary statements, see 44.4, 51.1, 58.1, and 65.1.
Note 2—This standard resembles IEC 60394–2 in title only. The content is significantly different.
^REFERENCE:ASTM Standards:
D92 Test Method for Flash and Fire Points by Cleveland Open Cup Tester
D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
D150 Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation
D257 Test Methods for DC Resistance or Conductance of Insulating Materials
D374 Test Methods for Thickness of Solid Electrical Insulation
D689 Test Method for Internal Tearing Resistance of Paper (Withdrawn)
D902 Test Methods for Flexible Resin-Coated Glass Fabrics and Glass Fabric Tapes Used for Electrical Insulation
D1711 Terminology Relating to Electrical Insulation
IEC Standard:
IEC 60394–2 Varnished Fabrics for Electrical Purposes
