Traditionally, maximum motor speed has been 60Hz for motors controlled by VFDs. Sometimes, it is necessary to have a higher upper frequency limit. Danfoss VFDs can run at output frequencies higher than 60Hz.
This is especially useful if you are just a little bit short of water/air at full speed, but the motor is still running below its nameplate full load amps (FLA).
No matter what-- you don't want to run the motor above the FLA, and you may want to confirm that mechanically it is OK (motor/fan/pump/belts) to spin faster in your application. The VFD doesn't care as long as you are below its rated outputs.
Here’s an example of changing the maximum output frequency from 60Hz to 75Hz.
To change the maximum frequency output on the VFDs from 60Hz to 75Hz, update the following three parameters:
3-03 Maximum Reference = 75Hz
4-14 Motor Speed High Limit (Hz) = 75Hz
6-15 Terminal 53 High Ref/Feedback Value = 75Hz --- or whatever input you are using for the speed reference.
After you make these changes to the limits, slowly walk the speed up to the max in "Hand", making sure that the motor amps don't exceed the nameplate FLA.