Shaft power N
—
Pump Shaft Power & Motor Selection
Shaft power N = γ·Q·H/(3600·1000·η) · Motor power P = K·N/(ηt·ηd)
m³/h
m
0–1
kg/m³
0–1
Safety factor K by pump power
| Pump power | Safety factor K | Drive efficiency | Motor efficiency |
|---|
System Head & HVAC Pump Selection
Pump head H = (H1 + H2 + H3) × safety factor, then shaft power & motor
H₁ — Piping friction loss (fittings segments)
Enter each pipe segment: nominal diameter (sets reference friction per meter), length and friction rate (Pa/m). Head = length × rate ÷ (ρ·g).
| Segment / DN | Length (m) | Friction rate (Pa/m) | Friction head (m) |
|---|
H₂ — Local (fitting) losses
Enter each fitting type, quantity, local loss factor ζ and flow velocity. Loss = 0.5·ζ·ρ·V²/ρ/g (metres of head). Figure either from this list or enter the total directly.
| Fitting | Qty | ζ | Velocity (m/s) | Local head (m) |
|---|
m
1.0–1.2
kg/m³
m³/h
0–1
Pump Installation Height (Suction / NPSH)
Correct the allowable suction vacuum [Hs] for altitude & water temperature, then subtract velocity head and suction loss to obtain the allowable installation height.
m
m
m
°C
m
hB=KBQ²
m
Water vapor pressure by temperature (m H₂O)
Pipe Velocity & Diameter Sizing
A = π·D²/4; V = Q / A. Choose which value to compute.
m/s
Design reference — recommended flow velocity by pipe size
| Pipe size | Velocity | Friction (Pa/m) |
|---|
Pump Anti-Vibration (Spring Isolator) Selection
Disturbing frequency f = n/60; natural frequency f0 = √(g/δ)/(2π); frequency ratio λ = f/f0; transmissibility T = 1/(λ²−1).
rpm
kg
pcs
mm