With the Sion 3AE5, Siemens has developed its most compact vacuum circuit breaker for air-insulated medium voltage switchboards up to 12 kV. Compared to its predecessor the Sion 3AE5 is 30 percent smaller in volume, which means that switchgear manufacturers can now build switchboards that are more compact than ever before. With less space required for switchboards, costs are also reduced. Circuit breakers are the most important elements of a switchboard – they reliably switch all operational currents and residual currents, protecting the distribution network and the connected loads against short circuits.

Sion vacuum circuit breakers are used in medium-voltage distribution networks for example to provide switching functionality for outdoor lines, cables, transformers, generators, capacitors, filter circuits, motors and reactor coils. Thanks to a modular and flexibly adaptable design, the new vacuum circuit breaker is easy to integrate in all standard air-insulated medium voltage switchboards.

Siemens used the latest technologies to reduce the dimensions of the Sion 3AE5 vacuum circuit breaker to a minimum. For all voltage levels the dimensions are the same: 540 mm high, 447 mm wide and 390 mm deep. This reduces not only the space needed in the switchboard but also the amount of planning work. In addition the user can choose between various pole center distances. Similarly there is a choice of distance between the top and bottom connections. Switchgear manufacturers can therefore build a switchboard in various designs for different applications.

The new vacuum circuit breakers also contribute to a better ecological footprint: by using less material and more modern technologies Siemens has reduced CO2 output during production by around 30 percent. Also, only minimum quantities of oil and lubrication grease are needed.

Siemens offers various accessory packs that are designed to greatly simplify the installation of the circuit breakers in the cubicles. The packs include a withdrawable module, contact arms, fixed contacts and feed-throughs. It is also possible to expand the circuit breakers into devices with full communication capability by means of an external relay, e.g. a Siprotec Compact 7SJ80 machine protective relay.

Sion 3AE5 vacuum circuit breakers are design-tested in accordance with IEC 62271-100. The number of maintenance-free operating cycles exceeds 10,000.