Load break Switch FN!2-24DR, IEC420

Load Break Switch FN12-24DR Indoor use. with earthing switch and fuse holder. Electric Function: Rated Voltage: 24kV Maximum Service Voltage:25.8kV Withstand Voltage to earth and between poles:50kV Withstand voltage across the isolating distance:60kV Impulse withstand voltage to earth and between poles:125kV Impluse withstand voltage across the isolating distance:145kV Rated current: 400A 630A 800A Breaking capacity for active circuits (cos Ø0.7): 400A 630A 800A Breaking capacity for no-load transformers: 16A Breaking capacity for no-load line and cables: 25A Short-time current:20kA/1s Making Capacity:40kA MAIN FEATURES In the switch disconnectors series FN12 and FN12 P the moving contacts operate vertically, and interruptio is caused by their quick separation under a blow of compressed air, created by a fixed piston mounted in the lower part of the pole: this blow of air impacts onto the electric arc, with a strong deionisation effect which quenches the arc within a few milliseconds from the moment of contact separation. The great effectiveness of the interruption is due to the specific shape of the blowing nozzle, which prevents the arc from wandering in the interruption gap, and delivers a precise stream of compressed air onto the fixed contact in the exact moment when it leaves the nozzle. A second important element contributing to a perfect control of the arc is the special shape of the upper insulator, called "bell insulator", inside which operates both the fixed and the moving contacts, perfectly aligned with each other: at the moment of the interruption, the arc is positively "held" inside the bell insulators, so that no risk occurs that may wander toward one of the other phases. During the interruption, therefore, the three phases remain perfectly isolated one from the other: this fact, joined with the duration of the air blow (injected on the arc along the whole contact stroke), enables the switch disconnector series FN12 to interrupt inductive currents of many Ampere, as well as normal currents of many hundreds of Ampere, with the introduction in the circuit of a large arc resistance which ensures that no dangerous overvoltages are created and let through to cables and machines. This system of autocompression of the air enables the switch disconnector series FN12 to carry out many hundreds of interruptions, without requiring any kind of service or maintenance, unlike other types of switches, using gas autogenerating components. Moreover, the light weight of the moving elements enables the LBS series Fn12 to attain a high number of mechanical operations, without evidencing mechanical problems. Package