IEC 60947-5-8-2020 Low-voltage switchgear and controlgear – Part 5-8: Control circuit devices and switching elements – Three-position enabling switches

IEC 60947-5-8-2020 Low-voltage switchgear and controlgear – Part 5-8: Control circuit devices and switching elements – Three-position enabling switches. These switches are used as components of enabling devices to provide signals that, a) when activated, allow machine operation to be initiated by a separate start control, and b) when de-activated, initiate a stop function, and prevent initiation of machine operation. NOTE 1 The enabling control function is described in 9.2.3.9 of IEC 60204-1:2016 but the application of threeposition enabling switches is not limited to a component of the enabling device described in IEC 60204-1. NOTE 2 This document does not deal with enabling devices. These switches are intended to be connected to circuits which rated voltage does not exceed 250VAC50Hz/60Hzor300VDC. EXAMPLE Devices incorporating three -position enabling switches are: push-button enabling devices; grip actuated enabling devices; foot actuated enabling devices. See Annex A for more typical examples. This document does not apply to: three-position enabling switches for non-electrical control circuits, for example hydraulic, pneumatic; enabling switches without three-position mechanism; emergency stop devices (see IEC 60947-5-5). 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60068-2-1:2007, Environmental testing- Part 2-1: Tests- Test A: Cold IEC 60068-2-2:2007, Environmental testing- Part 2-2: Tests – Test B: Dry heat IEC 60068-2-6:2007. Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal) IEC 60068-2-27:2008, Environmental testing – Part 2-27: Tests 一Test Ea and guidance: Shock IEC 60947-1:2020, Low-voltage switchgear and controlgear – Part 1: General rules IEC 60947-5-1:2016，Low-voltage switchgear and controlgear 一Part 5-1: Control circuit devices and switching elements – Electromechanical control circuit devices 3 Terms and definitions For the purposes of this document, the terms and definitions given in Clause 3 of IEC 60947-1:2020 and Clause 2 of IEC 60947-5-1:2016, and the following apply. Iso and IEC maintain terminological databases for use in standardization at the following addresses: ●IEC Electropedia: available at ht://ww.electropedia.org/ ●ISO Online browsing platform: available at ht://ww.iso.org/obp Alphabetical index of definitions 3.1 enabling device manually operated control device used in conjunction with a start control and which, when continuously actuated, allows a machine operation 3.2 three-position enabling switch three-position switch having enabling contact(s) 3.3 actuating system <three-position enabling switch>...