Enter flow and system conditions — get total dynamic head, NPSH available, power and the recommended motor.
Open the free calculator →A pump has to overcome the total dynamic head (TDH) of your system while staying safely above cavitation limits. EnggiBasis takes your process conditions and returns the head, the power, the NPSH margin, and a motor size — so you specify the right pump the first time.
TDH is the difference between discharge and suction head:
TDH = (H_static + ΔH_pressure + H_friction,discharge) − H_suction
i.e. the elevation the fluid is lifted, plus the pressure difference expressed as head, plus the friction losses in the piping.
P_hydraulic = ρ · g · Q · H and P_shaft = P_hydraulic / η
where Q is volumetric flow, H is TDH, ρ is density, g is gravity and η is pump efficiency. The motor is selected above shaft power with a margin.
NPSHa = (P_atm − P_vap)/(ρg) + H_suction,static − H_suction,friction
NPSHa must exceed the pump's NPSH required plus a safety margin — otherwise the pump cavitates.
Sizing, not guessing: EnggiBasis outputs the head and power from your system data. It also flags an NPSH shortfall before you buy the wrong pump.
| Input | Value |
|---|---|
| Flow rate | 50 m³/h |
| Total dynamic head | 40 m |
| Fluid density | 1000 kg/m³ (water) |
| Pump efficiency | 70% |
Result: hydraulic power ≈ 5.45 kW, shaft power ≈ 7.8 kW → a 7.5–9.3 kW (10 hp) motor with margin. Try it with your own numbers →
TDH = discharge head − suction head: static lift + pressure-head difference + friction losses in the piping.
NPSHa = (Patm − Pvap)/(ρg) + static suction head − suction friction. Keep it above NPSHr + margin to avoid cavitation.
Head and flow calculations are free. NPSH, power and motor selection are part of EnggiBasis Pro (₹99/month).
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