Two axes, one duty point
The horizontal axis is flow Q and the vertical axis is head H. Actual operation occurs where pump and system curves intersect. Maximum flow and maximum head normally belong to different points; do not combine them into a single duty. Check the speed, impeller diameter and frequency stated for the curve before comparing models.
Why BEP matters
BEP is the best efficiency point. Selecting near it, within the manufacturer’s recommended range, generally improves energy use and mechanical behaviour for sustained operation. A high efficiency percentage alone is insufficient. Review daily demand variation, parallel pump operation and standby requirements alongside the curve.
Read power and NPSH together
Matching the head curve is only one step. The motor must cover the permitted operating range, suction conditions must meet NPSH needs and the fluid must match the reference assumptions. A water curve may need correction for a viscous liquid. The diagram below is illustrative, not a guaranteed performance curve for a specific product.
Let’s select the right product.
Your contact information and a short description are enough to start. Add flow, head, fluid and quantity if known; we can clarify the rest together.