SITOR fuses protect power semiconductors from the effects of a short circuit because the super-quick disconnect characteristic is far quicker than that of conventional LV HRC fuses. They protect expensive devices and system components such as converters with fuses in the input and in the DC link, UPS systems and soft starters for motors.
Panel mounting requirements have given rise to various connection versions and designs.
The fuses with blade contacts comply with IEC 60269-2 and are suitable for installation in LV HRC fuse bases, in LV HRC switch disconnectors and in switch disconnectors with fuses. They also include fuses with slotted blade contacts for screw fixing with 110 mm mounting dimension, whose sizes comply with IEC 60269-4.
Fuses with slotted blade contacts for screw fixing with 80 mm or 110 mm mounting dimension are often screwed directly onto busbars for optimum heat dissipation. Even better heat transmission is provided by the compact fuses with M10 or M12 female thread, which are also mounted directly onto busbars.
Bolt-on links with 80 mm mounting dimension are another panel-mounting version for direct busbar mounting.
The fuses for SITOR thyristor sets, railway rectifiers or electrolysis systems were developed specially for these applications.
To find out which LV HRC fuse bases and safety switching devices can be used with the SITOR fuses, please refer to the chapter "Low-voltage fuse systems".
The characteristic curves for the configuration and assignment of SITOR fuses to fuse bases and 3NP and 3KL safety switching devices can be found in the Catalog ET B1 Add-On Characteristic Curves and on the Internet.
The new size 3 type ranges have a round ceramic body instead of a square one. Key features of these type ranges are small I²t values with low power dissipation and a high alternating load capability. The dimensions and the functional dimensions comply with the current standards IEC 60269-4/EN 60269-4 (VDE 0636-4).