VSD's and PF

[skip.delclos]

It is common in VSD literature to state that PF correction can be achieved through use of these devices. Yet our data collected in the field suggest that PF improvement is very small, if any. Is there concrete data and/or a VSD product that shows significant PF improvement? Thanks

 

[jim dungar]

The vast majority of VFDs are built diode bridge input sections. These bridges inherently have a better PF than do 'lightly loaded' standard motors.

While a VFD improves the PF of the individual motor circuit, it likely does little to improve the facilities PF.

 

[skip.delclos]

Thank you Jim

 

[Besoeker]

The vast majority of VFDs are built diode bridge input sections. These bridges inherently have a better PF than do 'lightly loaded' standard motors.

Better displacement power factor but worse distortion power factor.