This article is to give you some insight for VFD applications when using the Fluke-377 FC or Fluke-378 FC.
VFD's produce RF radiation that interfere with FieldSense AC voltage measurements. Use the test leads for measuring voltage on conductors in the vicinity of VFD's.
The FieldSense technology is also not intended to measure the voltage or current output signals of a variable-frequency drive (VFD) motor controller. (FieldSense technology is built into the Hard Jaw portion of the two Clampmeters.)
The workaround is to use the AC voltage mode and the test leads if you need to measure voltage in or out of the VFD, and use the iFlex mode and the iFlex current probe to measure the output current of the VFD.
The manual states the following: