Frequently asked questions

FA166718

25 October 2023

Issue:
Skipping output frequencies in an ATV61/ATV71

Product Line:
Altivar ATV61 and ATV71

Environment:
All

Cause:
Motor is making a noise when running within a certain speed range.

Resolution:
In menu 1.3 Settings, adjust the following parameters:
Skip Freq (JPF) = midpoint of the skipped range
Skip Freq Hysteresis (JFH) = number of frequencies to be skipped above and below the midpoint

This function prevents the VFD from outputting undesirable motor speeds.  It is typically used to skip over a resonance frequency range that can result in pronounced or excessive motor noise.

The skip frequency range is (JPF – JFH) to (JPF + JFH).  The JFH hysteresis is common to all 3 skip frequency functions (JPF, JF2 and JF3). 
 
Example :
Skip Freq = 30Hz
Skip Freq Hysteresis = 2
The skipped range will include 2Hz below and 2Hz above the 30Hz Skip Freq.
The total skipped range is 28Hz - 32Hz.