Ashful
Minister of Fire
Personally I rely on a clamp-on amp meter but I thought 746 would give Doc something to start with.
I just went through replacing the sub. pump on our 500 ft. well so I'm well acquainted now with pump curves and efficiencies. I looked into going with a variable speed pump but decided against it. We did all the (hard) work ourselves and I did spend a fair amount of time sizing and spec'ing out the pump and motor based on actual needs rather than rules of thumb.
You pulled a submersible pump from 500 feet yourself? I am impressed. I’ve done them, but never any nearly that deep! I hope you had some buddies to tag-team that bad boy, and lots of lawn space to lay out the pipe.
Yeah, clamp-on ammeter is the only way to go, on these things. Like stoves, every install is different.