Q: Can I use a Voltage Indicator on the motor side of a variable frequency drive?

 A: The voltage indicators are UL rated for 50-60 Hz and 400 Hz, but they will not be UL rated on the output of the variable frequency drive (VFD) as they can have frequencies in the KHz. If UL is not needed, the R-3W has been tested at up to 10 kHz levels and there will be no issues.