The unique benefits of  NFO Sinus

The NFO Sinus frequency inverter is based on our own patented technology which provides a pure sinusoidal voltage output. The inverter is therefore interference free, which brings with it a multitude of unique benefits.

All conventional frequency inverters use PWM technology – see the comparison with sinusoidal technology below.



Controlling electric motors with NFO Sinus is:

  • No shielded Cables

NFO Sinus complies with the EMC directive without a filter or shielded cables for all environments, from the industrial and agricultural sectors to residential buildings and hospitals.
Existing unshielded cables can be used and in older facilities there is no need for any rewiring.  In addition there is no requirement for EMC classed installation accessories, for example screw fittings and switches. Therefore installation is quick and you do not have expensive EMC class cables, so the cost of installation remains low.

Compare with PWM – all PWM inverters must be installed with EMC classed shielded cables and all installation accessories must be EMC classed.

  • No complicated installation requirements

There are no special EMC restrictions when it comes to NFO Sinus installation.

Compare with PWM – Tough requirements are in place for laying cables and the installer must often have special EMC skills.

  • No limitations on distance between motor and inverter

With NFO Sinus you can have a greater distance between motor and inverter – several hundred metres. The inverter can be placed centrally in an easy-to-service location – exactly where you want it. The only limitation is the cable’s resistance.

Compare with PWM* – The maximum distance between the inverter and the motor varies between different PWM inverters but is often limited to a few tens of metres.


  •  No electromagnetic interference

NFO Sinus nus provides sinusoidal voltage which means that the inverter is interference free – without any electromagnetic interference.

Compare with PWM* –  In PWM inverters the voltage is cut up into small pulses, which can lead to electromagnetic interference (both in cables and airborne).

  •  No irritating switching noise

With NFO Sinus there is no switching noise in the motor and giving silent and pleasant surroundings for both people and animals.

Compare with PWM* – When the current is switched in the transistors there is an irritating, high-frequency noise inside the motor.


  • No bearing currents

NFO Sinus does not give rise to any bearing currents and therefore the motor has a longer lifespan. NFO Drives provides a five-year guarantee on bearings for new motors.

Compare with PWM* – PWM technology creates electrical charges which wear the bearings in the motor. The sparks created make holes in the ball bearings. The motor bearings are therefore worn out quickly – sometimes within months.

  • No earth currents

NFO Sinus is free from earth currents therefore making it possible to use circuit breakers for both personal safety and fire prevention. No stray currents are generated and you avoid both interference with technological equipment and an unpleasant experience for animals.

Compare with PWM* – PWM inverters have such a high earth current that it is difficult to install them in a facility with circuit breakers and completely impossible with safety circuit breakers. Note also that the earth current increases with use of shielded cables, which is always required when installing PWM inverters!


PURE SINUS WAVE – that’s the difference!

*PWM = Pulse Width Modulation is used by all conventional frequency inverters on the market.