| 1 | Motor phase arrangement | Three stator phases: A, B, and C, separated by 120 electrical degrees. | A three-phase winding set produces a rotating magnetic field when phase currents are electronically sequenced. | Confirm winding configuration, terminal identification, phase resistance, and back-EMF symmetry. |
| 2 | Electronic commutation method | Six-step, or trapezoidal, commutation. | The inverter advances through six valid switching states during one electrical cycle. | Check controller compatibility, commutation timing, switching protection, and firmware support. |
| 3 | Number of active states | Six active states per electrical cycle. | Typical conduction sequence includes A+ B−, A+ C−, B+ C−, B+ A−, C+ A−, and C+ B−. | A useful benchmark for verifying phase order, Hall-sensor mapping, and controller setup. |
| 4 | Conduction angle | 120 electrical degrees per phase, in the conventional 120° conduction scheme. | Each phase conducts for two-thirds of an electrical cycle and remains floating for the remaining 60 electrical degrees. | Review the motor’s back-EMF shape and controller conduction mode before selecting a drive. |
| 5 | Commutation interval | 60 electrical degrees per switching step. | One electrical revolution contains 360 electrical degrees divided into six commutation sectors. | Use oscilloscope testing to verify correct transition timing and avoid torque dips or current spikes. |
| 6 | Phase state during each step | Two phases are energized while the third phase is normally floating. | One high-side and one low-side inverter switch typically establish current flow through two motor phases. | Evaluate freewheel paths, dead time, MOSFET or IGBT ratings, and current-sensing accuracy. |
| 7 | Rotor position feedback | Three digital Hall sensors commonly provide six valid logic combinations. | Hall transitions are commonly spaced at 60 or 120 electrical degrees, depending on sensor placement and motor design. | Request Hall sequence, electrical zero position, signal voltage, and allowable timing tolerance. |
| 8 | Electrical frequency | fe = p × n / 60, where p is pole pairs and n is mechanical speed in r/min. | Electrical cycles occur more frequently than mechanical revolutions when the rotor has more than one pole pair. | Use pole-pair count and rated speed to size controller bandwidth, sampling rate, and switching strategy. |
| 9 | Back-EMF waveform | Trapezoidal back-EMF is normally matched with six-step current control. | A flat back-EMF region supports approximately constant electromagnetic torque when rectangular phase current is correctly timed. | Compare measured phase-to-phase back-EMF, flat-top duration, imbalance, and distortion across production samples. |
| 10 | Torque-ripple considerations | Commutation torque ripple can occur at each 60° electrical transition. | Winding inductance, device switching time, Hall placement, back-EMF distortion, and current regulation affect ripple. | Ask for speed-torque curves, acoustic data, thermal results, and ripple measurements at the intended operating point. |