The sphere gaps can be used for Impulse, AC or DC voltage calibration according to the IEC 60052 recommendation. The sphere-gap presents the undeniable advantage of a direct and straightforward voltage measurement, where only the sphere diameter and their distance give a voltage measurement within ± 3 % accuracy.

As both spheres are mounted on columns of insulating material in the horizontal sphere gaps, it’s possible to superimpose impulse, alternating and direct voltages for special tests. For the chopping of lightning impulses, the sphere gap can be equipped with the optional chopping device KFS Z.

The type designation consists of the characters KFS, H for horizontal design and V for vertical and the sphere diameter in mm, e.g. KFS H 250.

Designed for indoor operation. The spheres are made of highly polished copper with tight manufacturing tolerances.

In the horizontal design, they are mounted together with the adjusting gear on supporting columns. The adjusting gear consists of a hand-wheel and precision scale for adjustment of the sphere gap (accuracy 0.5 mm).

The vertical, motorised design includes the sphere drive placed on the base frame. The sphere distance is controlled by the impulse generator controls (Ex. GC 257) or by a specific control unit (Ex. GSC 219).