Variable Speed Drive Calculators for Pumps

It is standard engineering practice to oversize pump capacities by at least 10% to accommodate unknown installation configurations. The over capacity of the pump has a “cubed” effect on electrical operating cost. For example a 10 Hp pump reduced in speed by 10% will only use 7.0 Hp (30 % less power).


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Pumps - Variable Speed Drive

 
Nameplate Horsepower 50 
Nameplate Efficiency 81% 
Motor Load at Pump 0.90 
Annual operating hours 8000 
Existing Flow Control Throttling Valve 
Local Utility Rate ($/kWh) .08  $/kWh
Pump Loading
Percent of Capacity
(gpm)
Percent of Time at
this Capacity
10% %
20% %
30% %
40% %
50% %
60% %
70 % %
80% %
90% %
100% %