Electric Motors
VFD Energy Savings Calculator
Estimate estimated power after speed reduction with VFD Energy Savings. The page keeps the formula, assumptions, and example values visible.
Enter values for estimated power after speed reduction
Use one consistent electrical operating case for all fields.
How VFD Energy Savings works
The page evaluates P₂ = P₁ × speed fraction³. VFD Energy Savings uses Original fan power, Speed fraction to report Estimated power after speed reduction.
With the loaded values, estimated power after speed reduction evaluates to 7.68 kW. Test one input at a time and save the original case.
Inputs for VFD Energy Savings
Original fan power and Speed fraction belong to VFD Energy Savings. Keep source units with original fan power.
The initial entries illustrate operation only. Use current records, readings, or nameplate values for planning.
- Original fan power
- Example entry: 15 kW.
- Speed fraction
- Example entry: 0.8.
Reading the VFD Energy Savings result
This output represents VFD Energy Savings.
Use the result as a planning quantity before checking available ratings and protective requirements.
Measurement and units
Motor nameplate data, duty, enclosure, starting method, load profile, and thermal limits govern final selection. Check prefixes on original fan power.
Normalize units before judging one electrical case against another.
Limits of this calculation
The cube law applies to suitable variable-torque loads.
This worksheet does not model every behavior in the surrounding system. Unentered effects remain outside VFD Energy Savings.
VFD Energy Savings record notes
Record source and operating details for original fan power. Compare this result with Motor Capacitor Calculator when capacitive reactance target is also needed.
Retain raw estimated power after speed reduction beside its selected rating.
Questions about VFD Energy Savings
What does VFD Energy Savings calculate?
VFD Energy Savings reports estimated power after speed reduction.
Can Original fan power be zero?
For VFD Energy Savings, measure any zero original fan power directly.
Why can estimated power after speed reduction differ from measurement?
The cube law applies to suitable variable-torque loads. Recheck original fan power.
Should the result be rounded?
Keep extra digits while comparing cases, then round to the precision supported by original fan power.