A new algorithm has been developed for the PPA3500 precision power analyzer which enables 7 phase power measurement utilizing only 6 wattmeters. With the new “7 Phase” mode the engineer is able to obtain true 3 phase measurements when connected in a 3 Phase 2 Wattmeter wiring configuration. Previously, only SUM parameters were able to be determined when connected in a 3 phase 2 wattmeter configuration – these restrictions no longer apply.
See APP note 36 for more information – https://d34v9rzb0weal6.cloudfront.net/uploads/2014/04/APP036-%E2%80%93-6-7-phase-motor-drive-analysis.pdf