Versatile NO Contactor

Press Release

Munich, 10 March 2021: In most modern applications, contactors and other electromechanical switchgear are used for emergency stop situations only. In normal operation, switching is implemented by the power electronics. The contactors are only responsible for galvanic isolation and only have to work under load in emergencies, i.e. in very difficult conditions.

In the event of a fault, a contactor has to carry powerful currents and may have to be able to disconnect them. Typical applications include battery-powered vehicles such as electric buses, electric HGVs, electric vans, electric cars or forklifts, as well as driverless transport systems in logistics applications. Contactors are also used for battery management systems in battery storage systems, charging stations, inverters and engine or battery test systems. The contactors must fulfill the required electrical parameters, while also being as compact and energy-efficient as possible.

Air contactors with improved properties

Schaltbau’s C300 series features contactors that are ideal for a range of modern applications. The latest contactor from this series is the C320 – a NO contactor with a nominal operating voltage of DC 1,500  V and a thermal continuous current of 1,000  A. The extremely compact air contactor measures just 190 mm x 166 mm x 79 mm. As a result, it is roughly 30 % smaller and 30 % lighter than previous air contactors. They have significant advantages for mobile applications in particular, for example in battery-powered vehicles.

The C320 is equipped with an electronic economy circuit with a variety of benefits:
In operation, the contactor has a very low holding power due to the very high contact pressure forces and the resulting low contact resistances via the main contacts. It is just 8 W – only roughly 50% of the power required by other contactors on the market. They are very energy-efficient, which is especially important for battery-powered electric vehicles. Thanks to the C320’s high contact pressure forces, the contact resistance is very low, as is the temperature increase. The high contact pressure forces also permit a high rated short-circuit switching capacity of 4,000  A and a very high short-term current capacity of 5,000  A for 1 s. These values differ significantly from the devices established on the market in this performance class. The C320’s threshold switching capacity – 1,500  V and 800  A – is very high with a low inductive load. Based on these excellent performance figures, the device fulfills outstanding safety standards.

Ideal for electromobility applications

The C320 works bidirectionally – i.e. it can disconnect loads in both current directions without restrictions. Bidirectionality is essential for all applications where current can flow in either direction. For example, charging and discharging batteries or braking energy recuperation in electromobility applications. The contactor complies with the standards both for contactors in industrial applications EN60947-4-1 and for railway applications EN60077-1. It offers shock and vibration resistance, which is vital for the automotive sector, in accordance with ISO16750-3.

Schaltbau GmbH

Connect – Contact – Control. The Schaltbau GmbH Group develops and produces electromechanical components and innovative driver’s cabs for the railway and industrial sectors based on this three-word mission statement. The company has been guaranteeing safety in rail transit since 1929, and currently protects systems in renewable energy, electromobility and automation applications. Schaltbau is dedicated to creating safe solutions for customer applications, and has set itself strictest safety standards to achieve that.


Schaltbau GmbH

Hollerithstrasse 5
81829 Munich


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