ASTM F1689-05(R2020) pdf free download
ASTM F1689-05(R2020) pdf free download.Standard Test Method for Determining the Insulation Resistance of a Membrane Switch
1. Scope
1.1 This test method covers the determination of the insu- lation resistance of a membrane switch. 1.2 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.3 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Terminology
2.1 Definitions: 2.1.1 insulation resistance—the electrical resistance be- tween test points. 2.1.2 leakage current—current flow through the insulation between test points. 2.1.3 membrane switch—a momentary switching device in which at least one contact is on, or made of, a flexible substrate. 2.1.4 test points—two preselected conductive points in a circuit loop, possibly including a switch.
3. Significance and Use
3.1 Insulation resistance is useful for design verification, quality control of materials, and workmanship. 3.2 Low insulation resistance can cause high leakage cur- rents. 3.3 High leakage currents can lead to deterioration of the insulation or false triggering of the associated input device, or both. 3.4 Specific areas of testing are, but not limited to: 3.4.1 Conductor/dielectric/conductor crossing point. 3.4.2 Close proximity of conductors, and 3.4.3 Any other conductive surface such as shielding or metal backing panel. 3.5 Insulation resistance measurement may be destructive and units that have been tested should be considered unreliable for future use.
4. Interferences
4.1 The following parameters may affect the result of this test: 4.1.1 Humidity, 4.1.2 Contamination, 4.1.3 Barometric pressure, and 4.1.4 Temperature.
5. Apparatus
5.1 Electric Device, suitable to provide a constant prese- lected dc voltage and suitable electronic monitoring device to measure very small current levels (micro-ampere range), or 5.2 Resistance Measuring Device, such as a megohm-meter, or equivalent that can provide a specified voltage. (This would replace 5.1.)
6. Procedure—Voltage Source Method (Fig. 1)
6.1 Pretest Setup: 6.1.1 Connect test points of the switch assembly to the voltage source. 6.1.2 Connect leakage current measuring device in series with the voltage source. 6.2 In-Process Test: 6.2.1 Adjust voltage source to 100 VDC 6 10 % or as specified. 6.2.2 Dwell for 60 s. 6.2.3 Record leakage current.
7. Procedure—Megohm Method (Fig. 2)
7.1 Pretest Setup: 7.1.1 Connect test points of the switch assembly to the megohm-meter.7.2 In-Process Test: 7.2.1 Adjust megohm-meter to 100 VDC 6 10 % or as specified. 7.2.2 Dwell for 60 s. 7.2.3 Record insulation resistance.
