DANSK DSF/PREN IEC 60947-5-8 PDF

This part of IEC 60947 series specifies requirements for 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 three- position 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 250 V AC 50 Hz/60 Hz or 300 V DC. 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).