BLDC Motor Tools

Welcome to this collection of tools and information for brushless DC (BLDC) motors. Whether you're rewinding a motor, building one from scratch, or just trying to understand motor characteristics, you'll find useful calculators and reference material here.

Winding Schemes

Learn about common winding patterns for BLDC motors including CD-ROM (9N12P), dLRK, and LRK configurations. Visual diagrams show how to wire the stator teeth for each phase.

Scheme Calculator

Interactive calculator to generate winding schemes for any slot/pole combination. Enter your motor's slot and pole count to see the optimal winding pattern with visual representation.

Motor Constants

Calculate and understand key motor constants: Kv (velocity constant), Io (no-load current), and Rm (winding resistance). Includes efficiency calculator with copper/iron loss analysis.

More Info

Additional reference material including Delta vs Wye termination comparison, winding diagram tables, and practical tips for motor builders.

Quick Reference

Common Motor Configurations

Configuration	Slots (N)	Poles (P)	Common Use
CD-ROM	9	12	Small motors, CD/DVD drives
dLRK	12	14	Model aircraft outrunners
dLRK	12	10	High-speed outrunners
Large Motor	24	20	EV motors, e-bikes
Hub Motor	27	30	E-bike hub motors

Key Formulas

Kv (drill press method) = RPM / (Volts × 1.414 × 0.95) Kv (running motor) = RPM / (Volts - Amps × Rm) Kt = 1/Kv (in SI units: RPM in rad/sec) Torque = Kt × Amps Efficiency = Power Out / Power In Copper Loss = Amps² × Rm Iron Loss = Volts × Io