IEC 61234-2:1997 pdf download – Electrical insulating materials -Methods of test for the hydrolytic stability -Part 2: Moulded thermosets

IEC 61234-2:1997 pdf download – Electrical insulating materials -Methods of test for the hydrolytic stability -Part 2: Moulded thermosets.
This part of IEC 61234 describes the test method for the determination of the hydrolytic stability of moulded thermosets made of room temperature or oven-Curing reaction resins when subjected to the simultaneous influence of water and high temperature With this test method. the irreversible change of mechanical and electrical properties is measured, but no mechanical stress is imposed on the test specimens.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of lEG 61234. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreement based on this part of IEC 61234 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below Members of IEC and ISO maintain registers of currently valid International Standards.
lEG 60212:1971, Standard conditions for use prior to and during the testing of solid electrical insulating materials
IEC 60250:1969, Recommended methods for the determination of the permittivity and dielectric dissipation factor of electrical insulating materials at power, audio and radio frequencies including metre wavelength
lEG 60455-2:1977, Specification for solventless polymerisable resinous compounds used for electricai insulation — Part 2: Methods of test
lEG 60584-1:1995, Thermocouples — Part 1: Reference tables lEG 60584-2:1982, Thermocouples — Part 2: Tolerances
Amendment 1(1989)
Iso 527-2:1993, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and extrusion plastics
3 Properties to be measured
Changes in the electrical and mechanical properties are determined In accordance with the
International Standards specitied below.
3.1
dIelectric dIssipatIon factor and permlttlvlty
See clause 37 ot IEC 60455-2 which refers to IEC 60250.
3.2
tensile strength
Tensile strength of the specimen is measured in accordance with ISO 527-2.
4 Test specimens
4.1 DIssipation factor and permittivity
The dimensions of the test specimens for the evaluation of dissipation factor retention versus temperature shall be (100 ± 1) mm x (100 ± 1) mm x (1 ± 0.1) mm. The same test specimens shall be measured prior and after the immersion test (clause 7) for each temperaturetime combination used.
lithe preparation of lest specimens of 1 mm thickness is not possible (due to high viscosity or high filling rate of the reaction resin), test specimens of 3 mm t 0,1 mm shall be used.
4.2 Tensile strength
At least three individual test specimens shall be tested for each property evaluated at each test temperature and time. For the determination of the properties of the untreated moulded thermosets 10 test specimens shall be used. Unless otherwise specified, the dimensions for the test specimens shall be in accordance with type I B of ISO 527-2.
5 ConditIoning
Test specimens prepared from room-temperature curing reaction resins shall be stored 24 h at room temperature in accordance with IEC 60212 and finally cured for 24 h at 80 C.
The test specimens prepared from oven-curing reaction resins shall be conditioned according to the manufacturers recommendation in order to obtain well cured specimens. The test specimens shall be tested immediately after oven curing and conditioning at room temperature or stored in a desiccator prior to testing. After the bath immersion, the test specimens shall be dried at 60 C ± 2 K for 48 h at an absolute pressure of less than 100 Pa and then stored at room temperature for a minimum of 8 h In a desiccator prior to further testing.
6 Apparatus
6.1 Agelng vessel
The ageing vessel shall have a minimum volume of 5 [
For pressure vessels, not more than 5 % water loss is permissible after 1 000 h at the test temperature. The material of the ageing vessel shall be chosen so that the ageing vessel is able to satisfy the following calibration inertness test. Demineralized water according to 7.2 is heated at the highest test temperature 140 C ± 2 K for 1 000 h. The pH of the water as measured after the inertness test shall not change from 7,0 ± 0,5 to more than 7.0 ± 1.5 and the conductivity shall not extend beyond the range of 500 pS/m to I 000 pS/rn.
Specimens prepared from room-temperature curing reaction resins can be aged in a glass container covered with aluminium foil.