Both impeller trimming and variable frequency drives can cut pump energy, but they solve different problems. If you treat them as interchangeable, you can end up with a "savings" project that either fails to meet process needs or carries unnecessary life cycle cost. The fastest way to stay out of trouble is to apply the Golden Rule: trimming is for constant excess head from an oversized pump, while speed control is for variable demand where your system curve shifts over time. That single line will...
