NFO Sinus Optimal 5.5 kW Sine Wave Frequency Converter
The NFO Sinus Optimal 5.5 kW frequency converter is based on a patented Swedish technology that controls the speed of electric motors without generating electromagnetic interference. Because the output voltage is a pure sine wave, the converter is interference-free in itself – intrinsic EMC – and offers a range of unique advantages over conventional PWM drives.
The 5.5 kW model covers motors with a rated current of 3.5 to 11 A and is a frequent choice for borehole and booster pumps, ventilation fans and process machinery.
Installation is simple and cost-effective: no shielded cables, EMC filters or other EMC-classified accessories are needed, and existing unshielded cables can be re-used in renovation and energy-efficiency projects. The only limit on the cable length between converter and motor is the resistance of the cable, so the NFO Sinus can be installed where it suits the application best, even several hundred metres from the motor.
NFO Sinus generates no bearing currents, so the motor lasts longer, and no earth leakage currents (< 2 mA), so residual current devices (RCDs) can be used for both personal and fire protection. The motor speed is controlled very precisely, with full torque from standstill and at low speed, and the energy-save function reduces consumption further when the motor runs at low load.
Main features
- Pure sine-wave output voltage – no electromagnetic interference, no switching noise in the motor
- No shielded motor cable and no EMC filters required – certified according to EMC Directive 2014/30/EU
- No distance limit between converter and motor except cable resistance
- No bearing currents – longer motor life
- Earth current < 2 mA – RCDs for personal and fire protection can be used
- Full torque from standstill; frequency (0–150 Hz), speed (0–9000 rpm) or PI process control
- Safe Torque Off (STO) with dual-channel wiring for emergency stop
- Modbus RTU/ASCII, RS-485 and USB built in; PROFIBUS, PROFINET or Modbus TCP via Anybus CompactCom module
- Energy-save function and IE2 efficiency class (CDM) according to Ecodesign Regulation 2019/1781
- IP55 enclosure; free NFO Sinus Manager software
Applications
- Pumps – water supply, boreholes, booster stations, fountains and water features
- Fans and ventilation (HVAC), including hospitals and residential buildings
- Agriculture and livestock farms – no earth currents that disturb animals
- Food industry, healthcare and other sensitive environments
- Conveyors, polishing and process machinery – several identical motors in parallel
Technical data
| Rated motor power | 5.5 kW |
| Continuous current rating | 3.5 – 11 A |
| Maximum current | 13.3 A |
| Input | 3 × 380–480 V ±10%, 50/60 Hz ±10% |
| Output | 3 × 0–380/480 V, 0–150 Hz |
| Output voltage waveform | pure sine wave |
| Operating mode | 4-quadrant |
| Control modes | frequency 0–150 Hz; speed 0–9000 rpm; PI process control with feedback |
| Control signals | 2 analog inputs and 2 analog outputs (0–10 V, 2–10 V, ±10 V, 0–20 mA, 4–20 mA, ±20 mA); 7 fixed setpoints; 24 V sensor supply |
| Relay outputs | 2 × programmable (common alarm, run indication), max 1 A / 50 VDC |
| Acceleration / deceleration | 0.5 – 100 s |
| Motor protection | PTC / Klixon thermistor input; Power guard overload protection |
| Personal safety | Safe Torque Off (dual channel) |
| Communication | Modbus RTU / ASCII, NFO Classic, USB, RS-485; PROFIBUS / PROFINET / Modbus TCP (Anybus CompactCom) |
| Earth current | < 2 mA |
| EMC | EMC Directive 2014/30/EU – certified for use without shielded cables and filters |
| Efficiency class (CDM) | IE2 (Ecodesign Regulation 2019/1781, EN 61800-9-2) |
| Protection class | IP55 |
| Ambient temperature | -10 … +45 °C (storage -20 … +60 °C), 0–90% RH non-condensing |
| Dimensions H × D × W | 390 × 190 × 200 mm |
| Weight | 9.5 kg |
| Part number | NFO 4B4D3111D |
| Option | brake resistor / brake chopper |
NFO Drives product brochure – NFO Sinus Optimal 1.5–18.5 kW (PDF)
Read more about how NFO Sinus sine-wave technology works. Contact us to choose the right model and for a quote.
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