text: <s>[INST] Harmonic Filter with PowerFlex700 drives Summary: Use one Harmonic Filter with multiple PowerFlex700 drives Hello dears, I am designing a RO system which we are using almost 15 PF700 drives (11KW=10 and 5.5KW=5) in same MCC room. I want to use single Harmonic filter (Low Pass) with all VFDs. My two questions as below 1- Harmonic filter for the PF700 required or not required to meet the IEEE-519 standard (according to the IEEE-519 it should be 5-8%)? 2- One Harmonic filter with 15 VFDs is workable or not? Please advice accordingly. [/INST] You need to use an Active harmonic filter for multiple drives, remember to also use a input choke on each drive. This will reduce the active filter size. A complete harmonic analysis is required to size the unit. You need the KVA / fault rating and impedance of the supply transformer, cable lengths and the amount of linear load on the same feeder. Here is a link to a calculator tool http://webdc.transim.com/rockwell/ If all the drives are operating at the same time then just add the kw's as one large drive \\n </s>