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For detailed instructions - see our "User and Installation Guide" and "Quick Installation Guide". You will find these here


Frequently asked questions with answers

Below you see some of the questions we usually get. If you have more questions, please contact us.

  • Which version of the manual should I use for the NFO converter?

It depends on which version of inverter you have. If the inverter has a two-row terminal block for signal wiring - use manual version 2.x. If the inverter has a three-line terminal block for signal wiring - use manual version 3.x. Printing date of the manual: Ver 3.1 – 2006-06-01 / ver 3.2 – 2007-05-02 / ver 3.4 – 2009-03-19 / ver 3.5 – 2012-01-04

  • The inverter starts but does not run the motor/pump etc

Check that the drive signal is connected to terminal 5. See figure 1 in the manual. Is positive or negative logic used?  Check jumper S1 – se figure 3 in the manual. Check that the driving signal is correctly connected depending on the logic. Check that Autotuning is done with the correct engine data, chapter 5.5 in the manual

  • It says "Stop" in the display. How do I change to drive mode?

Hold down SHIFT and press STOP to enter External mode.


  • It alarms "AC Fail".

The AC Fail alarm is due to input voltages to the inverter and not the inverter itself. Check the mains voltage.

  • I get "PTC Temp" alarm.

Is an engine protectormistor (correctly) connected? PTC ballast resistor should only be present if motor protection thermistors are used.


  • I get the alarm "ImagnLow" during installation.

Check that the motor is connected to the inverter and that all switches between the inverter and the motor are turned on.


  • Can I install NFO Sinus without filters and without shielded cables?

Yes, the converters meet the standards in the EMC Directive 2004/108/EC for emissions from equipment in homes, offices, shops and similar environments (EN 61000-6-3) and immunity for equipment in industrial environments (EN 61000-6-2) without additional accessories or shielded cables. The directive entered into force on 20 July 2007.


  • How can I reset all parameters (factory reset)?

Follow the instructions in chapter 5.13 of the User and Installation Manual (chapter 5.12 of the 2.x manual).


  • What does Intrinsic EMC mean?

This means that the equipment is interference-free in itself and can be installed without EMC filters, shielded cables or other EMC-rated installation accessories.


  • Can you run several motors in parallel on a frequency converter?

Yes, it is possible if the engines are the same size and equally loaded. Enter the sum of the current and power to all motors during auto-tuning in the parameters I-Nom and P-Nom. For other parameters, the value for a motor is entered.


  • Can earth fault circuit breakers be used together with NFO Sinus?

Yes, it works perfectly - also earth fault circuit breakers for personal protection. An NFO Sinus draws a maximum of 2 mA in the earth conductor and earth fault circuit breakers for personal protection break at 30 mA. Earth fault circuit breakers for fire protection break at higher currents depending on where they are installed.

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