ASTM D3755 Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials Under Direct-Voltage Stress
ASTM D3755在直流电压作用下固体电绝缘材料介电击穿电压及介电强度标准试验方法
This test method is intended for use as a control and acceptance test for direct-voltage applications. It may be used also in the partial evaluation of material for specific end uses and as a means for detecting changes in material due to specific deteriorating causes.
Experience indicates that the breakdown value obtained with direct voltage usually will be approximately 2 to 4 times the rms value of the 60-Hz alternating-voltage breakdown.
For a nonhomogeneous test specimen, the distribution of voltage stress within the specimen is determined by impedance (largely capacitive) with alternating voltage. With an increasing direct voltage, the voltage distribution may be still largely capacitive, but depends partly on the rate of voltage increase. After steady application of direct voltage the voltage division across the test specimen is determined by resistance. The choice of direct or alternating voltage depends upon the purpose for which the breakdown test is to be used, and to some extent, on the intended application of the material.
A more complete discussion of the significance of dielectric breakdown tests is given in Appendix X1 of this method and of Test Method D 149. Those appendix sections of Test Method D 149 that refer to alternating voltage are not applicable to the direct-voltage method.
1. Scope
1.1 This test method covers the determination of dielectric breakdown voltage and dielectric strength of solid electrical insulating materials under direct-voltage stress.
1.2 Since some materials require special treatment, reference should also be made to ASTM specifications or to the test method directly applicable to the material to be tested. See Test Method D 149 for the determination of dielectric strength of electrical insulating materials at commercial power frequencies.
1.3 This test method is similar to IEC Publication 243-2. All procedures in this test method are included in IEC 243-2. Differences between this test method and IEC 243-2 are largely editorial.
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. Specific precaution statements are given in Section 7.
2. Referenced Documents (purchase separately)
ASTM Standards
D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
D176 Test Methods for Solid Filling and Treating Compounds Used for Electrical Insulation
D877 Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes
D1711 Terminology Relating to Electrical Insulation
D2436 Specification for Forced-Convection Laboratory Ovens for Electrical Insulation
D3487 Specification for Mineral Insulating Oil Used in Electrical Apparatus
D176 Test Methods for Solid Filling and Treating Compounds Used for Electrical Insulation
D877 Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes
D1711 Terminology Relating to Electrical Insulation
D2436 Specification for Forced-Convection Laboratory Ovens for Electrical Insulation
D3487 Specification for Mineral Insulating Oil Used in Electrical Apparatus
ANSI Standard
ANSIC68.1 Techniques for Dielectric Tests, IEEE Standard No. 4.
IEC Standard
IEC243-2 Methods of test for electric strength of solid insulating materials--Part 2: Additional requirements for tests using direct voltage
Index Terms
conditioning; creepage; criteria of breakdown; dielectric breakdown voltage; dielectric strength; direct voltage; direct voltage stress; electrodes; flashover; rupture; solid insulating materials; surrounding medium; voltage control; voltmeter;