Johnson Controls PENN VFD68 - Parameter Settings Calculations for Motor Speed Vs. Pressure; PWM Frequency, Audible Motor Noise, and EMI

VFD68 Variable Frequency Drives (575 VAC)
25
The drive can be configured to display operating frequency (Hz) or motor speed (RPM). To display motor
speed (RPM) instead of operating frequency (Hz), set P. 37 to the rated motor RPM value. See Adjusting the
Default Parameters on page 26.
Parameter Settings Calculations for Motor Speed vs. Pressure
Note: To use a 0–10V or 4–20mA P499 Transducer, refer to the VFD68 Variable Frequency Drive Technical
Bulletin (Part No. 24-7664-3051).
PWM Frequency, Audible Motor Noise, and EMI
Using the default setting (P. 72 = 1, frequency = 1 kHz), electromagnetic interference (EMI) radiation and
leakage current from the wiring between the VFD68 Drive and the motor is low; however, there is a high level
of audible motor noise. As the setting for P. 72 increases (up to P. 72 = 15, frequency = 15 kHz), audible motor
noise decreases while EMI radiation and leakage current increases.
If the audible noise from the VFD is too great with P.72 set to 1, increase the setting to 4 and listen to the
audible noise. To minimize the EMI radiation, use the smallest number possible for P. 72.
Figure 16: Calculating Parameters for Applications Using One or Two
0.5–4.5 V Ratiometric Transducers