Power selection of industrial frequency inverter

The AC output frequency of a power inverter device is usually the same as standard power line frequency, 50 or 60 hertz. The exception is in designs for motor driving, where a variable frequency results in a variable speed control.

Due to their high efficiency, they offer the advantage of energy saving, especially for continuous operation applications. However, from the point of view of efficiency, it is always necessary to consider the system as a whole. Frequency inverters have an efficiency of > 95 %.

Overloads or dynamic applications may require assignment of an inverter with a higher power. For a 1:1 assignment of the motor to the inverter, up to 2x the nominal torque is possible. In theory, the motor itself can provide up to 3x the nominal torque (when starting and in the limited speed range).

All NORD frequency inverters can operate NORD synchronous motors. In principle, NORD synchronous motors can be operated with inverters from other manufacturers. Several devices from our competitors have been successfully tested with our motors. The customer is responsible for the success of commissioning.

NORD synchronous motors can only be operated with inverters. NORD synchronous motors cannot, or can only be operated to a very limited extent in the weak field range. By their rotation, the permanent magnets in the rotor induce a voltage in the stator, which opposes the terminal voltage.