Sizing Your Motor Before You Configure
The Configurator Guide walks through every card on the configurator page in detail. This guide is the step before that: what to work out about your application first, so the numbers you enter are close to right on the first pass rather than something to discover by trial and error inside the tool.
Nominal Speed and Torque, From Your Operating Point — Not a Peak
The configurator's mechanical output properties card asks for a nominal speed and nominal torque. These should describe where the motor spends most of its running time — its steady-state operating point — not a peak or stall figure. If your application's load varies, work out the continuous, sustained torque the way the direct-drive motor sizing guide describes: from the duty cycle, not from the single largest number the load ever produces. Entering a peak figure as the nominal torque will size a motor larger, and often heavier, than the application actually needs.
DC Bus Voltage, Fixed by What You Actually Have
The electrical supply properties card needs the DC bus voltage your application will actually supply — a battery pack's nominal voltage, or a fixed supply rail. This isn't a design choice the configurator makes for you; it's an input fixed by your system, and getting it right up front avoids redesigning the winding later because the back-EMF was matched against the wrong number.
Envelope: Diameter and Axial Length Limits
Before touching the rotor and stator cards, know the physical envelope your motor must fit within — the maximum outer diameter and axial length your application can accommodate. Axial flux motors are wide and thin rather than narrow and long, so the envelope question is usually about diameter headroom and axial depth budget, not shaft length. If the envelope is tight, expect the torque density question to dominate the rest of the design.
Current Density and Thermal Environment
How the motor will be cooled, natural convection, forced air, or conduction through a mounting structure, sets how much continuous current density the winding can actually sustain, independent of what the analytical results card shows as an instantaneous figure. If you don't yet know the cooling path, treat the configurator's analytical current density warning as provisional rather than final, and confirm it against your actual thermal environment before committing to a design, per the general electric motor temperature considerations.
Torque Ripple and Positioning Tolerance, If Applicable
If your application holds position or moves at low speed, rather than simply spinning continuously, decide upfront how much torque ripple is acceptable. This isn't a configurator input directly, but it affects how you read the results afterward — see the robot joint and actuator motor selection guide if your application is this kind.
What You Should Have Before You Start
- A nominal (continuous, steady-state) speed and torque, not a peak figure.
- The DC bus voltage your system actually supplies.
- Maximum outer diameter and axial length your envelope allows.
- A rough idea of your cooling path, even if approximate.
- For positioning applications: how much torque ripple is tolerable.
With these in hand, start with guide 1 of the Configurator Guide for the page layout and recommended workflow, then guide 2 to enter the numbers above.
Related Terms
- Configurator Guide — the step-by-step walkthrough this guide feeds into.
- Direct-drive motor sizing guide — a fuller method for arriving at a continuous torque figure from a duty cycle.
- Robot joint and actuator motor selection guide — if positioning accuracy and ripple, not just torque and speed, matter for your application.
- Torque and power density — the reference guide for whether your envelope and torque target are compatible.