Control circuit devices and switching elements — Three-position enabling switches
IEC 60947-5-8-2020 pdf download.Low-voltage switchgear and controlgear — Part 5-8: Control circuit devices and switching elements — Three-position enabling switches
Appareillage a basse tension — Partie 5-8: Appareils et éléments de commutation pour circuits de commande — Interrupteurs de commande de validation a trois positions.
9.3.3.6 DurabilIty
9.3.3.6.1 General
The three-position enabling switch shall successfully pass the mechanical and electrical durability tests described in 9.3.3.6.2 and 9.3.3.6.3.
Minimum test operations: 100 000 cycles
Recommended test operations: 0.1 — 0,3 — 1 — 3 — 10 — 30 — 100 million operations
9.3.3.6.2 Mechanical durability
The three samples (see 9.1) shall be subjected to the following test.
The test shall be performed for minimum 50 000 cycles of position 1 —, 2 —* I operation and minimum 50 000 cycles of position 1 -4 2 —, 3 — 1 operation. The actuator of a three-position enabling switch shall be subjected to the forces necessary to achieve the required positions.
The maximum rated operating force specified by the manufacturer (see F5 as defined In Figure 2) is applied at position 3.
The movement and actuating forces of the three-position enabling switch shall be consistent throughout the test. This shall be verified by measurement before and after the tests.
The mechanical durability of the three-position enabling switch is defined as the number of no-load operating cycles which will be attained by all samples tested without repair or replacement of any part.
Tests shall be carried out according to C.1.2 of IEC 60947-5-1:2016.
During the test, the enabling contacts shall be checked at each change of state by the manufacturer at the conditions described below, and there shall be no failure.
Test voltage and current: 24 V DC, 10 mA maximum.
Test method: The agreement of switch position and enabling contact status shall be checked at every position before shifting to the next position.
The enabling contact status shall be checked at each position. The three-position enabling switch shall be shifted to the next position only when the agreement of switch position and contact status has been confirmed. When any disagreement of position and contact status is found, tests shall be stopped.
During the tests, there shall be no electrical and/or mechanical failures. Following the tests. the switching element shall pass the dielectric test of 8.3.3.4 of IEC 60947-5-1:2016 with a test voltage equal to 2 U0 with a minimum of 1 000 V.
9.3.3.6.3 Electrical durability
The test conditions are those of 9.3.3.6.2 except that the circuit of the switch is energized according to the manufacturer’s specified ratings in accordance with 6.1. item g).
9.3.3.7 Robustness
The actuator shall withstand a force of 150 % of the maximum rated operating force specified by the manufacturer (see F5 as defined in Figure 2), applied three times in the direction of normal operation In a manner simulating human action.
9.3.4 Performance under conditional short-circuit current Subclause 8.3.4 of IEC 60947-5-1:2016 applies.
9.3.5 Shock and vibration tests
9.3.5.1 Conditioning procedures
The purpose of the following procedures Is to expose the three-position enabling switches to
various environmental conditions in order to verify their functioning after such exposure. The three three-position enabling switches shall be subjected to the following exposures:
— 96 h at +40 °C in dry atmosphere according to test Bb of IEC 60068-2-2;
— 96 h at +5 ec according to test Ab of IEC 60068-2-1.
Following the environmental exposures and after the samples have been restored to room temperature, the sequence of tests in 9.3.5.2 and 9.3.5.3 shall be conducted.
9.3.5.2 Shock
The three three-position enabling switches that have been conditioned in accordance with 9.3.5.1 shall be tested in each of the three mutually perpendicular axes.
Each three-position enabling switch is tested in position 1 and shall withstand 15 g shock in both directions of each axis according to IEC 60068-2-27: 11 ms — 15 g.
During the test, no closed contacts shall open and no open contacts shall close.IEC 60947-5-8-2020 pdf download.