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VARIUS fuse switch-disconnectors

We are introducing three additional sizes – FH1, FH2 and FH3 – for rated currents of 250A, 400A and 630A. VARIUS fuse switch-disconnectors replace the previously supplied LTL1, 2 and 3 switch-disconnectors. The first member in this series, the FH000 switch-disconnector, was introduced at the end of 2000.

A new series of fuse switch-disconnectors was completed in the design department for fuse devices and was subsequently put into production. This series was introduced to the market under the trade name VARIUS.

Introducing a wholly new series was justified by the fundamental and comprehensive modernisation of these devices, which created new advantages for producers of switchboards, as well as for designers and service personnel. No less important today is the modern design unifying OEZ’s protection devices. Especially because of its modular design, the new series features greater flexibility and faster delivery terms.

VARIUS type FH fuse switch-disconnectors are produced from materials that are heat resistant and have excellent impact resistance. The base is made from fibreglass-reinforced polyester, while the other casings are from glass-filled polyamide. The inspection window is from polycarbonate. The contacts are produced from electrolytic copper and are silver-plated.

To ensure high reliability in quenching, the device is fitted with standard quenching chambers. In addition to the basic design (FH-3A/F), it is also possible to order a design with remote signalling of the fuse conditions (FH-3S/F). A 1-pole version is also available in all sizes, including a version with remote signalling.

What are the features of the new VARIUS series?

Switchboard manufacturers will appreciate first and foremost the new possibility for rear connection. This variant, which can be assembled with the help of one of the connecting sets that are offered, provides for attractive savings in installation work, when, for example, one bend can be saved in connecting the busbar from the main connection.

Owing to the enclosed connection area, which is to be chipped off only according to the type of connection used, no additional cover for IP20 protection is needed for mounting on a board. On the contrary, the design of the auxiliary covers, which may be needed for installation using cable lugs or bare busbars, brings the additional advantage in simple joining of any number of covers to cover the desired length.

Moreover, the covers are identical for both upper and lower sides. Among other advantages are easy assembly of four-pole and two-pole versions using a simple assembly kit, an option for modular assembly of all the accessories and, last but not least, adapters for installation on busbars with a universal cable outlet upward or downward. Another innovation is that the VARIUS switch-disconnectors sizes 1, 2 and 3 are, in contrast to the LTL models, supplied with sets of connecting bolts.

Designers will appreciate that the VARIUS line offers one-pole switch-disconnectors of all sizes, an option for signalling of the fuse condition in three-pole and one-pole versions by mechanical means, and, thus, inexpensively with the use of simple fuse-links, the possibility for double signalling of the cover position for all models. Offered, too, is a wide range of connecting sets that include the innovative rear connection already mentioned.

Service personnel will certainly be interested in the nearly perfect visibility of the fuse-links within the switch-disconnector. Several innovations are offered to increase safety. Each of the switch-disconnectors is equipped with a mechanism for releasing the blown fuse-link from outside of the device, thereby eliminating the possibility of being burnt by the fuse-link, which can be extremely hot right after it blows.

As an accessory, one may purchase a locking insert that allows locking the switch-disconnector with a padlock (e.g., without fuses during maintenance work on the branch). Also available is a barrier against accidental contact in case that the switch-disconnector is supplied from the bottom side and voltage therefore appears at the fuse-link’s upper contacts.

The VARIUS switch-disconnector’s technical parameters are in many cases better than those of the heretofore supplied LTL switch-disconnectors. In sizes 1, 2 and 3, for example, conditional short-circuit current up to 120 kA was achieved in a 400V network and complied with impulse withstand voltages Uimp = 12 kV. The highest level of handling safety is already the standard for OEZ’s switch-disconnectors. That is defined as utilisation category AC23 for 400V networks.

A full summary of technical parameters, accessories and dimensions can be found in the new “Fuse Systems” catalogue.