Focusing on Measuring, Monitoring and Control of Current, Voltage

Power and Energy

Variable Frequency Drive (VFD)

Variable Frequency Drive (VFD)



Detecting VFD Proof Of Flow With Current Sensor

The challenge with monitoring variable frequency drives (VFDs) is the necessity to monitor both amperage and
frequency to ensure the drive is operating normally. To monitor this ratio, a current sensor must learn the VFD curve
and alarm the controller when the relationship is outside the normal operating range. VFD current sensors are
installed on the load side of the variable frequency drive and use a microprocessor to set the proper threshold.
The sensor will detect motor undercurrent conditions such as belt loss, coupling shear, and mechanical failure
on fans and pumps