SPM Motor Calculator

Magnetic Equivalent Circuit (MEC) analysis for Surface Permanent Magnet motors

Motor Configuration

Rotor Configuration

Rated Speed (RPM)

Friction & Windage Loss (W)

Solver

⚡ MEC — Magnetic Equivalent Circuit Client-side analytical solver · No FEA license required

Inner Rotor SPM

🧱 Material Selection

▼

Stator Steel

Rotor Steel

Magnet Material

Winding Material

🔵 Stator Geometry

▼

Stator Outer Diameter (mm)

Stator Inner Diameter (mm)

Number of Slots (Qs)

Number of Poles (2p)

Slot Bridge Hs0 (mm) Slot bridge height

Slot Wedge Hs1 (mm) Slot wedge height

Slot Body Depth Hs2 (mm) Main slot body height

Slot Opening Bs0 (mm) Slot opening width at air-gap

Slot Top Width Bs1 (mm)

Slot Bottom Width Bs2 (mm) Tooth width ≈ slot_pitch − Bs2

Corner Radius R1 (mm)

Corner Radius R2 (mm)

🔴 Rotor Geometry (SPM)

▼

Rotor Outer Diameter (mm)

Rotor Inner Diameter / Shaft (mm)

Magnet Thickness / Lm (mm) Radial magnet thickness

Pole Embrace (0–1) Magnet arc / pole pitch ratio

Mechanical Air Gap (mm)

Magnet Reduction (mm) Magnet-to-rotor-bore gap (if any)

📐 Stack & Skew

▼

Core Stack Length (mm)

Enable Skew

Skew Type

Skew Angle (degrees)

Inner Rotor — Stator & SPM

Winding Configuration

Winding Type

Wire Diameter (mm)

Strands per Turn (parallel wires)

DE End Overhang (mm)

NDE End Overhang (mm)

Parallel Paths per Phase (a)

Winding Temperature (°C)

Winding Layout Table

Coil #	In Slot	Out Slot	Phase	Turns

Winding Calculations

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Slot Fill Factor

—

Slot Area (mm²)

—

DC Resistance per Phase (Ω)

—

Resistance @ Temp (Ω)

—

Mean Turn Length (mm)

—

Series Turns / Phase

Operating Point

Motor Speed (RPM)

Drive Method

Peak Phase Current (A)

DC Bus Voltage (V)

Loss Configuration

Motor Temperature (°C)

Magnet Axial Segments

Magnet Radial Segments

Copper Loss (I²R)

Core Loss (Bertotti — Eddy + Hysteresis)

Magnet Eddy Current Loss

Simulation Modules

Back-EMF & Open-Circuit Flux

Torque & Torque Ripple

Torque–Speed Curve

Efficiency Map

MEC Solver

⚡ MEC

Analytical d-q model with Carter's coefficient air-gap correction, Bertotti core loss model, and field-weakening for the torque–speed envelope.

Initializing…

Simulation Results

No results yet. Run a simulation from the Simulation tab.

Drive

DC Bus Voltage—

Available Phase Voltage—

id (d-axis current)—

iq (q-axis current)—

Max Speed—

kt—

ke—

Material & Weights

Stator Material—

Rotor Material—

Magnet Material—

Stator Weight—

Rotor Weight—

Winding Weight—

Magnet Weight—

Total Weight—

Rotor Inertia—

Torque

Average Torque—

Max Torque—

Min Torque—

Torque Ripple—

Power & Losses

Speed—

Output Power—

Copper Loss—

Core Loss—

Magnet Loss—

F&W Loss—

Total Losses—

Input Power—

Efficiency—

Back-EMF (No Load)

RMS Phase Back-EMF—

Peak Phase Back-EMF—

Peak-to-Peak Back-EMF—

Back-EMF THD—

Air-Gap & Flux Density (No Load)

Air-Gap Flux Density (avg)—

Air-Gap Flux Density (peak)—

Stator Tooth B—

Stator Yoke B—

Rotor Yoke B—

Winding

DC Resistance (per phase, 20°C)—

Resistance @ Temperature—

k_ac Ratio—

Fill Factor—

Ld (d-axis inductance)—

Lq (q-axis inductance)—

ψ_pm (flux linkage)—

Winding Factor (kw)—

No simulation results yet. Run a simulation to generate graphs.