I am trying to measure the power factor of a single phase, 208V compressor motor that is connected across phases B & C of a three-phase service and drawing 8-10A. My first attempt using a Fluke 345 set to measure single phase is reading 0.997 power factor. If I set my meter to measure as three-phase, I see 0.07 power factor.
Neither of these can be correct and I'm not sure how to measure the true power factor for this setup. Is this even a reasonable measurement to ask for from this configuration?
(If it matters, there is another single phase motor connected across other phases (A & B) that is active at the same time and if I attempt to read it I get 0.47 or 0.88 power factor as single phase or three-phase measurement.)