13 Padlockable Motor Isolators Padlockable Motor Isolators IEC 60947-3 SWITCHES, DISCONNECTORS, SWITCH DISCONNECTORS IEC 60947 is a safety and performance standard for low voltage switchgear (up to 1000V). It has universally replaced IEC 408 and has combined specific requirements of many individual National Standards. IEC 60947 is a uniform standard for most countries around the world, and establishes a truly global market place. IEC 60947-3 is a section specific to switches. Importantly, it recognises that devices for the switching function and isolating function require very different performance criteria. Switching requires high performance of the current carrying parts to make and break loads under normal and overload conditions, e.g. motor applications. Isolation requires high insulation, sufficient spacing of current carrying parts and mechanical integrity, so that the handle corresponds to the actual contact position, so important for the safety of maintenance personal. The practicality of real life applications calls for three definitions within IEC 60947-3; Switches, Disconnectors and Switch Disconnectors. A Switch does not have to satisfy the isolation and mechanical strength tests, and a Disconnector does not have to satisfy the load tests. A Switch Disconnector must satisfy all tests, and is suitable for safety switch applications. A Disconnector must have a direct drive late make, early break auxiliary contact in series with a load breaking device (contactor) to be suitable as a safety switch. Kraus & Naimer have developed complete products which satisfy all IEC 60947-3 criteria, some of which are listed in this catalogue. For further information, please contact us. Note: See pages 95-97 for application guides.
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