Field notes
Pump energy
Wire-to-water efficiency, kWh per acre-foot, pump curves and VFD speed: the arithmetic behind what a well costs to run and what a pump repair returns.
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VFDs on water wells: when a drive pays for itself, and when it does not
The affinity laws promise big savings from slowing a pump. On a well lifting mostly static head, slow the drive 10% and you lose…
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Scheduling well pumps around time-of-use rates without missing your production target
The production target sets how many hours a well must run. The tariff decides which hours. The arithmetic, and the fifteen minutes that can…
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Critical speed and reed frequency: why your drive has a skip band
A vertical turbine on a drive has four frequencies that matter. Where a skip band comes from, what margin your evidence earns, and the…
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How to read a pump curve: BEP, operating range, VFD speed and the affinity laws
How to read a well pump curve: head, efficiency and horsepower curves, BEP and the preferred operating region, VFD speed in Hz and rpm,…
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How to read a pump efficiency test: wire-to-water efficiency, kWh per acre-foot and what the numbers cost
A pump efficiency test gives three numbers that matter: wire-to-water efficiency, kWh per acre-foot and the dollars recoverable. The arithmetic and the benchmarks.