Vacuum circuit breaker 3AK7 series

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Vacuum circuit breakers in the 3AK7 series are available in versions from 7.2 to 17.5 kV. The vacuum circuit breakers are very compact, with a distance between pole centers of just 210 or 280 mm, and they’re perfectly suited for use in medium-voltage switchgears thanks to their high mechanical strength and low space requirement. High-voltage and generator versions are available with the same dimensions and can be used for smaller generator switching applications in accordance with IEEE specifications up to 50 kA, and also for high-voltage applications. The powerful 3AH3 vacuum circuit breakers were the first 63- and 72-kA vacuum circuit breakers on the market tested in accordance with IEEE C37.013 for load currents up to 12,000 A and short-circuit currents up to 100 kA. In addition to the standard designs, we can also offer phase-segregated versions with separate switching units. The low resistance in the main current path allows the 3AH3 vacuum circuit breaker to be used with operating currents of up to 6,300 A with no forced cooling, or up to 8,000 A with forced cooling. These modular vacuum circuit breakers can also be installed horizontally using special cooling elements and are suitable for retrofitting in existing systems. The compact vacuum circuit breakers in the 3AH4 series are designed for up to 40.5 kV, and can handle up to 120,000 switching sequences. With minimal maintenance required – greasing the drives after 10,000 switching sequences and changing the vacuum tubes after 30,000 – these circuit breakers stay reliable throughout their entire service life, despite the tough mechanical demands they face.