Pwm Frequency, Audible Motor Noise, And Emi; Adjusting The Default Parameters; Vfd68Bxx And Vfd68Cxx Drives - Johnson Controls Penn VFD68D Series Technical Bulletin

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.

Adjusting the Default Parameters

VFD68Bxx and VFD68Cxx Drives

CAUTION: Risk of Property Damage.
!
Do not apply power to the system before checking all wiring connections. Short circuited or
improperly connected wires may result in permanent damage to the equipment.
MISE EN GARDE: Risque de dégâts matériels.
Ne pas mettre le système sous tension avant d'avoir vérifié tous les raccords de câblage. Des fils
formant un court-circuit ou connectés de façon incorrecte risquent d'endommager irrémédiablement
l'équipement.
Enter the Parameter Adjustment Mode
1. Remove the jumper that connects terminal SD to terminal STF.
IMPORTANT: Remove the jumper to stop the motor before you change the parameter values.
Figure 38: Applications Using 4–20 mA Transducers
VFD68 Variable Frequency Drives
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