With its 3KF product range, Siemens has developed new switch disconnectors with fuses for currents up to 800 A. Together with the switch disconnectors from the 3KD series that are capable of switching currents up to 1600 A, Siemens now covers virtually the entire product spectrum for low-voltage power distribution with its Sentron portfolio. The modular compact devices are suitable both for AC applications such as industrial plants, buildings and wind power, as well as for DC environments. Switch disconnectors safely protect users against electrical accidents during maintenance and installation work in switchgear cubicles. If necessary, padlocks can be used to lock the front panel or side panel mounted operating mechanisms. These prevent unauthorized switching and provide additional protection. Siemens offers the switches in five sizes, which are all available in three- and four-pole versions. They conform to standard IEC 60947-3 for low-voltage switchgear and the equipment-specific EC directives for product safety.
The combination of disconnectors and load interrupters are known as switch disconnectors. These perform the function of both technologies and enable electrical equipment to be switched on and off even under load. They are also suitable as repair switches if maintenance work is necessary on equipment in the de-energized state. They act as emergency stop switches in production lines to protect the operator in case of faults, and can also be used as master switches in floor distribution boards for disconnecting from the mains supply.
The 3KF switch disconnector offers a number of different protection systems. Cable connection covers for every application prevent contact with live parts. The state of the fuses is clearly visible through transparent contact covers. Clip-on phase barriers protect against flashovers, while an optional fuse monitor signals triggered fuses so that action can be taken immediately.
Installation of the switch disconnector is extremely simple. All variants can be fixed to mounting boards. Models up to 80 A additionally offer the option of mounting on DIN rails. Connections are possible in the form of box terminals (up to 80 A) or flat terminals (80 A upwards). The integrated test function checks the cabling of the control circuits during installation. The configuration of the switches can be altered and expanded quickly and easily. For example, a neutral conductor terminal, a fourth contact element or ground (N-PE) terminal can be easily retrofitted.
The portfolio is rounded out by service and support products. Various CAx files can be downloaded for mechanical and electrical planning, including equipment circuit diagrams, connection diagrams, dimensional drawings and 3D models. The CAx Download Manager provides a flexible solution for assembling all common planning tools.