CEI/IEC 60343:1991 pdf free download.Recommended test methods for determining the relative resistance of insulating materials to breakdown by surface discharges.
1 Scope
CEI/IEC 60343:1991 concerns endurance tests with surface discharges. It is intended to assess the relative resistance of solid insulating materials to breakdown when exposed to surface discharges.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 60, HIgh-voltage test techniques.
IEC 212: 1971, Standard conditions for use prior to and during the testing of solid electrical insulating materials.
IEC 270: 1981, Partial discharge measurements.
3 Object and principle of test
Simple means are required for assessing the relative resistance of solid insulating materials to breakdown when exposed to surface discharges while stressed by electrical field strengths at frequencies used in industrial service.
Experience shows that endurance tests, taking as a criterion the complete puncture of the material in the presence of surface discharges from several types of electrodes, provide a similar and reproducible classification of materials with respect to this type of stressing, provided that dry air is circulated around the electrodes and over the surface of the specimen during the test.
4.1.1 Cylindrical electrode
A cylinder of 6 mm ± 0,3 mm diameter with the sharp edge removed to leave a 1 mm radius. This electrode with a mass not exceeding 30 g shall be normal to the surface of the specimen and rest upon it. With soft materials, a gap not exceeding 100 pm between this electrode and the specimen is permitted to avoid possible mechanical damage.
It is convenient to introduce very thin specimens (thickness less than 100 pm) between electrodes fixed 100 pm apart.
When necessary to reduce specimen capacitance and minimize thermal heating, cylindrical electrodes of less than 6 mm are permissible provided the radius of the electrode edge is maintained at 1 mm.
Figure 1 shows examples of two electrode arrangements which may be used. The arrangement shown in figure lb avoids the electrode being seated slightly canted on the specimen when a gap between electrode and specimen is not necessary. Other arrangements are possible.