Multiple Chopping Gap The multiple chopping gap is a originally patented Haefely development and is used to chop lightning impulses (on the front and on the tail) as well as switching impulses up to the highest voltages. The sphere distance is automatically adjusted by the controls GC 223, GC 257. In the automatic mode, their distance is set automatically in function of the charging voltage. The gap distance is displayed on these controls. The chopping is initiated by the first stage, having a triggering plug. The multiple chopping gap serves simultaneously as a load capacitor for the impulse generator and allows excellent reproducibility of the chopping time and does not distort the wave shape until the chopping point. A manual control box GSC 219 is available to adjust the gap distance standalone or with non-Haefely control systems. With a additional secondary unit the MAFS is also usable for some applications as a voltage divider. Rod gaps and sphere gaps (above 1000 kV) draw a substantial pre-discharge current prior to the voltage break-down, causing a voltage drop. This affects the comparison tests when testing power transformers. Design For indoor operation and mobile design. The HV units are made of stacked capacitors with inserted damping resistances. This active part is built in reinforced fibre-glass cylinders. Our active part technology is derived from our decadelong experience. The copper spheres have tungsten sintered inserts to reduce the burn-off. Their distance is set by a precise drive. The upper semi-sphere is attached to a movable frame which makes it possible to adjust simultaneously all partial spark gaps. The multiple chopping gaps are equipped with toroid electrodes. The electrodes are made of brushed aluminium. The electrode type is determined by the rated voltage. Fibre-glass struts are required when more than 2400 kV units are used. The H base frame of welded steel profiles is equipped with four swivel castors. Multiple chopping gap MAFS in front of an SGDA Multiple chopping gap MAFS 2400 Subject to change without notice.

Technical Data Type Rated impulse Rated impulse Capacitance Int. damping Min. clearance to Top electrode voltage LI voltage SI approx. resistance walls and ceiling type at standard conditions according to IEC 60060-1 (1989) and altitudes lower than 1000 m. Trigger range General for time-to-chop scattering: < ± 150ns Relative humidity <90% non-condensing for unchanged gap spacing, negative polarity approx. 20 % Operating temperature -5 ... + 45°C for unchanged gap spacing, positive polarity approx. 10 % Storage temperature - 20 ... + 50 °C with variable gap setting, both polarities 30 % to 100...