Electromechanical components for electronic equipment Basic testing procedures and measuring methods - Part 2: General examination, electrical continuity and contact resistance tests,
Scope
The tests contained herein, when required by the detail specification, shall be used for electromechanical components within the scope of Technical Committee No. 48 . They may also be used for similar devices when specified in a detail specification.
1 Test 1a: Visual Examination
1.1 Object
The object of this test is to detail standard methods for the visual examination of electromechanical components within the scope of Technical Committee No. 48.
1.2 General
The visual examination checks identification, appearance, workmanship and finish of an item against the relevant specification. Optical aids, as specified in Sub-clause 1.4; should be used when specified by the detail specification.
The visual examination is to a certain extent a subjective method. Care must be taken to come to a fair judgement. Defects, deviations from a given standard or changes due to stresses must be carefully differentiated according to their importance or significance.
1.3 Features to be examined
The following features shall be examined:
a) workmanship and finish;
b) marking;
c) materials;
d) surface finish, for example:
- traces of corrosion;
- colour (comparison with applicable colour standards or samples;
- degree of lustre (comparison with applicable standard, for example Boll's scale or sample);
- roughness, grooves, waves, scratches, furrows, holes, pores, depressions, crests, scales, cracks, burrs, flash, etc.;
- foreign material in and on the surface.
e) internal conditions of translucent materials (for example cavities, gaseous inclusions and flow lines, including inclusions of foreign matter);
f) condition and location of a lubricant (as far as can be visually ascertained);
g) loosened and detached parts (especially after stress).
1.4 Method of visual examination
The visual examination shall be carried out by one of the following methods:
a) with the naked eye (normal strength of vision, normal colour perception, at the most favourable viewing distance and with suitable illumination); or
b) with magnifiers, if specified.
For the purpose of this standard, special methods, for example using polarized light (for observing internal tensions in materials) or other indicators (for observing internal material cracks or pores), are not permitted unless explicitly required by the detail specification.
1.5 Details to be specified
Foreword I
IEC Foreword II
IEC Introduction III
SECTION ONE GENERAL EXAMINATION
Scope
1 Test 1a: Visual Examination
2 Test 1b: Examination of Dimension and Mass
2bis. Test 1c: Functional Operation (Switches)
SECTION TWO ELECTRICAL CONTINUITY AND CONTACT RESISTANCE TESTS
3 Test 2a: Contact Resistance - Millivolt Level Method
4 Test 2b: Contact Resistance - Specified Test Current Method
5 Test 2c: Contact Resistance Variation
6 Test 2d: Circuit Continuity at Microvolt Level (Deleted)
7 Test 2e: Contact Disturbance
8 Test 2f: Housing (Shell) Electrical Continuity
9 Test 2g: Stability of Contact Resistance (Deleted)
10 Test 2h: Resistance (Earthing) from Actuator to Mounting Bushing (Surface)
SECTION THREE INSULATION TESTS
11 Test 3a: Insulation Resistance
SECTION FOUR VOLTAGE STRESS TESTS
12 Test 4a: Voltage Proof
13 Test 4b: Partial Discharge
14 Test 4c: Voltage Proof of Pre-insulated Crimp Barrels
