NFO
Drives
AB
2021
201013
‐
2
Operating
and
Installation
Manual
4
Introduction
The frequency inverter described in this operating manual is used for frequency (Hz) or speed (rpm) control of
three-phase AC induction motors. This manual describes how to install and use the inverter.
Read the manual carefully before installing the inverter, to ensure you install it correctly and get the maximum
performance out of it.
The inverter has a patented switch circuitry that ensures the motor receives a sinusoidal voltage at all times, under
all operating conditions. This solves all problems related to conventional PWM based frequency inverters, e.g.
electromagnetic interference, ball bearing damage, high earth currents and high switching noise.
A 30mA rated RCD (earth leakage circuit breaker) can be used with this frequency inverter.
The inverter also uses the patent "Natural field orientation" which is a vector control method to give perfect speed
control of induction motors all the way from zero to full speed.
1 Safety
aspects
Always disconnect the inverter from the mains supply before working on any electrical- or mechanical installation
components.
Installation, maintenance and repairs must always be conducted by staff adequately trained and experienced for
the purpose.
Modifying or replacing any components of the inverter or its accessories will render the inverter warranty null and
void. Should the need for any modifications or replacements arise, always contact NFO Drives AB.
Components in the power section and some components in the signal section are connected to the mains supply
when the inverter is powered
.
WARNING!
Touching any components with the mains supply connected can be fatal. Always disconnect the
mains supply before opening the cover.
WARNING!
Even when disconnected from the mains supply, the inverter may still contain lethal voltages
due to its buffer capacitors. Always wait at least five minutes
to make sure no voltage remains before
working with the inverter.
WARNING!
The heat sink of the inverter may get hot, depending on operating conditions. Do not touch.
WARNING!
Spontaneous start. When controlled from a communication bus or remote unit, the motor may
start at any moment. Pressing STOP on the inverter is not sufficient, as bus master or remote unit may re-
gain control over inverter and start motor again. Disconnect run signal at terminal DIN1 to safely inhibit start.
For connection of mains supply, the inverter shall be permanently connected to fixed wiring including a circuit
breaker which must be used to ensure all-pole disconnection under overvoltage III conditions.
The inverter shall always be connected to protective earth (P.E.) when the mains supply is connected.
If the motor temperature sensor (PTC/Klixon) functionality is used, the sensor and its wiring must supply
adequate isolation and comply with installation requirements for the equipment in use.
The level of integrity offered by the drive control input functions – for example stop/start, forward/reverse and
maximum speed, are not sufficient for use in safety-critical applications without independent channels of
protection. All applications where malfunction could cause injury or loss of life must be subject to a risk
assessment and further protection provided where needed.
3006469-2022-04
