The KFW3 series air circuit breakers are applicable to power distribution networks with AC 50/60 Hz, rated operational voltage up to 690 V and rated current up to 8000 A. They distribute electric energy and protect lines, power supply equipment and motors against overload, undervoltage, short circuit and single-phase grounding faults.
The KFW3 series air circuit breakers are applicable to power distribution networks with AC 50/60 Hz, rated operational voltage up to 690 V and rated current up to 8000 A. They distribute electric energy and protect lines, power supply equipment and motors against overload, undervoltage, short circuit and single-phase grounding faults.
The breakers can be equipped with various intelligent controllers providing complete protection. Communication-type controllers offer a fieldbus interface for remote metering, regulation, control and signalling — the "four-remote" function. With a leakage current transformer and the matching controller, earth-leakage protection is also available.
| Key technical data | Value | Source |
|---|---|---|
| Series / Type | KFW3 Series Air Circuit Breaker | P4 |
| Frame sizes | 1600 / 2500 / 4000 / 5000 / 8000 | P5 |
| Rated operational voltage Ue | AC690V and below (unified) | P5 |
| Rated current In | 400–8000A | P5 |
| Poles | 3P / 4P | P5 |
| Standards | GB/T 14048.2, IEC 60947-2 | P5 |
| Certification | TÜV, CB, CE | P3 |
| Frame size rated current Inm | 1600 / 2500 / 4000 / 5000 / 8000 (A) | P5 |
| Rated insulation voltage Ui | 1250V (1600 frame); 1800V (others) (V) | P5 |
| Rated impulse withstand voltage Uimp | 12kV (1600 frame); 18kV (others) (kV) | P5 |
| Power frequency withstand voltage | AC3500V / 50Hz / 1min (V) | P5 |
| Neutral pole rated current | 100%In (1600/2500/4000); 50%In (5000/8000) | P5 |
| Rated ultimate short-circuit breaking capacity Icu (AC400V) | 55 / 66 / 85 / 100 / 135 / 150 (by breaking type) (kA) | P5 |
| Total breaking time (no additional delay) | 12–30 (ms) | P5 |
| Closing time | ≤70 (ms) | P5 |
| Expected mechanical life | 5000–15000 (maintenance-free); 10000–20000 (maintained) (次 / cycles) | P5 |
| Ambient temperature | -40 °C to +70 °C (℃) | P5 |
| Installation altitude | up to 5000 m (declare above 2000 m) (m) | P5 |
| Degree of protection | IP40 | P5 |
| Pollution degree | Degree 3 (级 / degree) | P5 |
The full Icu / Ics / Icm matrix per voltage level is available from the original catalog and on request. Values below are summary figures verified against the catalog.
Unit3 / Unit4 / Unit6 controllers with multiple protection curves; Unit6 adds an LCD panel and settings.
Source: P8–P13
DC24V / DC110V / DC220V; reliable trip between 70%–110% rated control voltage; 50 cm lead as standard, 100/150 cm optional.
Source: P8 / P38 等
Up to 10 NO + 10 NC independent contacts on KFW3; three-position and ready-to-close contacts optional.
Source: P14–P17
Model designation: KFW3 - □ □ □ (frame size, design code, poles — 4 for four-pole, blank for three-pole). Full ordering codes are listed in the catalog (P40); contact us with your rating requirements and we will confirm the code.
Tell us your application and rating requirements — we respond within one business day.