Eaton DS7 - 2.5 emergency switching off; 2.6 Protection

2 Engineering
2.5 emergency switching off
36 DS7 Soft starter 09/16 MN03901001Z-EN www.eaton.com
2.5 emergency switching off
DS7 soft starters fall under safety category B as defined in standard
EN 954-1. In other words, certain faults may remain undetected (thyristor
failure caused by overvoltage ￫ permanently conductive).
If the machine has more stringent requirements in accordance with
EN ISO 14121-1 “Safety of machines”, additional (external) measures must
be implemented in accordance with this standard.
2.6 Protection
The devices are protected with fuse devices shown in the Appendix
(￫ page 221). Different fuse devices are used depending on the type of
coordination required.
2.6.1 Type 1 coordination
The protective switches or circuit-breakers stated are used for cable
protection and motor protection. The DS7 soft starter may be damaged in
the event of a short-circuit at the output terminals (motor connection 2T1,
4T2, 6T3).
2.6.2 Type 2 coordination
In addition to the safety devices for type 1 coordination, superfast
semiconductor fuses are required for type 2 coordination. These fuses will
protect the thyristors in the DS7 soft starter from damage in the event of a
short-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.
NOTICE
Semiconductor fuses cannot ensure a cable protection function!
NOTICE
Protection against overvoltages in the supply network cannot be
provided with superfast fuses!