2 Engineering2.5 emergency switching off36 DS7 Soft starter 09/16 MN03901001Z-EN www.eaton.com2.5 emergency switching offDS7 soft starters fall under safety category B as defined in standardEN 954-1. In other words, certain faults may remain undetected (thyristorfailure caused by overvoltage → permanently conductive).If the machine has more stringent requirements in accordance withEN ISO 14121-1 “Safety of machines”, additional (external) measures mustbe implemented in accordance with this standard.2.6 ProtectionThe devices are protected with fuse devices shown in the Appendix(→ page 221). Different fuse devices are used depending on the type ofcoordination required.2.6.1 Type 1 coordinationThe protective switches or circuit-breakers stated are used for cableprotection and motor protection. The DS7 soft starter may be damaged inthe event of a short-circuit at the output terminals (motor connection 2T1,4T2, 6T3).2.6.2 Type 2 coordinationIn addition to the safety devices for type 1 coordination, superfastsemiconductor fuses are required for type 2 coordination. These fuses willprotect the thyristors in the DS7 soft starter from damage in the event of ashort-circuit on the output terminals (2T1, 4T2, 6T3 motor connections).The semiconductor fuses must be mounted externally on DS7 soft starters.The assigned fuse types are listed in the Appendix on page 221.NOTICESemiconductor fuses cannot ensure a cable protection function!NOTICEProtection against overvoltages in the supply network cannot beprovided with superfast fuses!