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MOTOR / TOOL 01

Pole pairs.

Find the magnetic pole count in your motor. Each north and south pole makes one pair.

START HERE / REAL BOARD REFERENCE

Spot the magnetic poles

HUB WHEEL REMOVED
Annotated electric skateboard photo. An arrow identifies the small rectangular magnetic poles around the mounted motor's outer ring. A magnified inset shows those pieces beside the copper stator coils. The removed wheel sleeve is on the ground.

The pink callout points to the magnet ring on this mounted hub motor. The orange copper windings and the removed wheel sleeve are separate parts. Open full-size image ↗

INTERACTIVE DIAGRAM

The magnet ring, simplified

SCHEMATIC

The diagram separates the magnetic rotor from the copper stator so you can see the pattern. Count the alternating N and S magnetic regions, then divide by two.

01 MAGNETIC ROTOR ↓ COUNT HERE
Illustrated hub motor magnetic rotorAlternating north and south magnetic poles line a rotor ring. Small dots at the rim represent fasteners and should not be counted.
02 COPPER STATOR
DON'T COUNT
THE COPPER TEETH
N MAGNETIC POLE S MAGNETIC POLE FASTENER / IGNORE

This is a teaching diagram, not an exploded view of one board. The little rim dots represent fasteners, which do not determine pole pairs. On the photographed board, the visible magnet ring stays with the motor when the wheel sleeve is removed.

THE CALCULATOR

Count the poles

01 / 02
POLES

Count the alternating magnetic regions around the rotor. Enter an even number from 2 to 60.

YOUR MOTOR HAS
7pole pairs
14 magnetic poles 7 pairs
OPTIONAL / RPM TO ERPM

Electrical RPM depends on how many pole pairs pass the stator in one physical revolution.

RPM
Electrical RPM— ERPM

Motor RPM × pole pairs = ERPM

THE SHORT VERSION

What am I counting?

01

Look at the rotor

On a typical hub motor, the magnets line the inside of the rotating outer shell. Their alternating north and south magnetic regions are the poles.

02

Divide by two

One north pole plus one south pole makes a pair. For example, 14 magnetic poles mean 7 pole pairs.

03

Ignore the hardware

Sleeve screws and copper stator teeth are different parts. Their counts do not tell you the motor's pole pairs.

A physical magnet piece can contain more than one magnetic region. Use the manufacturer's motor specification or measure the magnetic poles if counting pieces is unclear.

RESEARCH / FURTHER READING

Sources

01VESC Project: ERPM and pole pairsExplains the 14 magnetic poles → 7 pole pairs example and the RPM relationship.02Brushless hub motor buildShows how the rubber wheel, permanent-magnet rotor, and wound stator relate.03Hub motor research thesisDetails the outer-rotor layout used for electric skateboard hub motors.

The photo is an annotated visual reference, not a specification for your particular motor. Confirm pole count with its manufacturer when possible.