Motor Fundamentals & Efficiency3 / 13
Selecting the Right Motor Size
Oversizing is common and wastes energy; matching load to motor rating.
9 min read · Jacob Willis, Net Zero Lead · Last reviewed July 2026
Two decisions shape a motor's lifetime cost more than its efficiency class: whether it is the right size for its load, and what happens on the day it fails. Both are usually made badly, for understandable reasons: oversizing feels safe, and failure-day decisions get made at speed with production waiting. This lesson gives both decisions their proper arithmetic.
In this lesson
- 01The oversizing problem
- 02Rewind or replace: the failure-day decision
- 03Duty details that bite
- 04Sources and further reading