| Thanks Drew,
It looks fine. The curves are a little strange so I can't come close to guessing where the most efficient spot is. Usually it's a little above 1/2 flow. The pumps best efficiency point (B.E.P.) is between 80% and 85% of the shut off head. At this point there is little to no radial thrust on the impeller. Also the "power in" is closest to the "power out".
That's why I tell people that the maximum flow should not be used to select a pump. It has to do with the volute relative to the rotation speed, usually around 1800 RPM for our stuff. (As low as 1725 at full load.) I have to say that so no one can say I wasn’t accurate as Russ did on my post “Can anyone say algae. I was joking Russ but I doubt you care.
Steve is running some of his at maximum flow and things seem to be running fine.
I looked up the motor on the motor manufacturer’s site and couldn’t find them at the lower power ratings. The larger were running at 65 – 70% eff. That’s much lower than I would expect but Steve’s operation shows an efficient pump. Curious!
If I had a use for one soon, I'd get one just to see how it worked out. The power consumption Steve is posting looks very good. |