Project 05 / 06

Brushless DC
Motor Build

A brushless DC motor designed and assembled from raw components — stator coils wound by hand, rotor magnet spacing set for commutation timing, and measured speed checked against calculated RPM.

Year
Jan — Apr 2026
Context
PHYS 141 · Course project
Role
Design & build
Stack
Electromagnetics · Stator winding · Bench testing
Fig. 05 — Cross-section · Stator coils & rotor magnets
3-phase · Self-sustaining rotation

Overview

A brushless motor is a simple idea and an unforgiving build: it only keeps turning if the field the coils produce and the magnets on the rotor stay in step. I designed and assembled one from raw components rather than a kit, working from electromagnetic induction and Lorentz-force analysis — winding the stator coils by hand, setting the rotor magnet spacing that governs commutation timing, and then measuring the speed the finished motor actually turned against the RPM I had calculated it should.

What I built

01

Built from first principles

Designed and assembled a functional brushless DC motor from raw components, applying electromagnetic induction and Lorentz-force analysis to get from theory to a working prototype.

02

Hand-wound stator & commutation timing

Wound the stator coils and set the rotor magnet spacing to control commutation timing — the adjustment that took the motor from stalling to continuous, self-sustaining rotation.

03

Measured against predicted RPM

Measured the output rotational speed on the bench and compared it against the theoretically calculated RPM target, confirming the build matched predicted performance.

Stack

Electromagnetics Stator winding Rotor magnet spacing Commutation timing Bench measurement