Pole Pairs

A Pole Pair is a pair of magnetic poles consisting of one north pole and one south pole.

Pole pairs are commonly used in motor control calculations because they determine the relationship between the motor’s mechanical rotation and electrical rotation. VESC controllers use the number of pole pairs when calculating motor speed, rotor position, and FOC control parameters.

The number of pole pairs is calculated as:

Pole Pairs = Motor Poles ÷ 2

Motors with a higher number of pole pairs require more electrical cycles to complete one mechanical revolution.

The relation between mechanical and electrical RPM (ERPM) is

Mechanical RPM = Electrical RPM ÷ Pole Pairs

Example

A motor with 14 poles has:

14 ÷ 2 = 7 Pole Pairs

If the motor completes one mechanical revolution, the controller must generate 7 electrical revolutions of the rotating magnetic field.

⚠️ Motor poles is one of the motor parameters in VESC Tool and it is entered as twice the number of pole pairs. Entering an incorrect pole count will result in incorrect RPM calculations for efficiency and speed calculations in the gauges and connected displays. The core motor control algorithms do not use pole pairs anywhere; they use ERPM (Electrical RPM) internally.

In simple terms: a pole pair is one north pole and one south pole on the rotor of the motor; the number of pole pairs determines the relation between mechanical and electrical RPM.