ENGINEERING / REFERENCE REGISTER
Show the work.
Real reference machines. Documented model inputs.
Results with the assumptions left attached.
QUANTITY × REFERENCE MACHINE
What has been compared?
Selected public records. Open a cell for its machine’s conditions, values and source.
| Machine | Back-EMF | Torque | No-load loss | Heating | Resistance |
|---|---|---|---|---|---|
| Parviainen | Independent inputs | Derived target | Not in this register | Not in this register | Not in this register |
| Sahin | Independent inputs | Not in this register | Not in this register | Not in this register | Development check |
| Ghent · 4 kW | Fitted closure | Not in this register | Not in this register | Prescribed heating | Not in this register |
| Abdelli · IFPEN | Conditional inputs | Adjusted measurement | Measured comparison | Not in this register | Not in this register |
| Ghent · 26p / 24s | Not in this register | Not in this register | Not in this register | Not in this register | Derived phase target |
Inputs and fitting matter. Independent inputs describe how the model was specified; they do not declare a completed validation pass. Fitted closure reuses a fitting target. Sahin’s resistance informed end-turn development, so it is a development check.
Derived is different from directly measured. Parviainen’s torque is inferred from EMF; Ghent’s phase resistance is derived from coil measurements. Abdelli’s torque includes a shaft-to-electromagnetic adjustment. Prescribed heating tests thermal response, not predicted loss generation.
“Not in this register” means no comparison is shown here. It is neither a zero result nor a statement that the quantity cannot be calculated. Read the evidence qualifications →
SELECTED COMPARISON
Method: q-axis sweep · graded axial grid
Loaded torque across the current range.
Four q-axis predictions differ by approximately −0.2% to +3.4% from the adjusted measurement. The published current angle is unknown; this is a bounded comparison, not a general accuracy claim.
Operating conditions
Abdelli / IFPEN · 1,000 rpm · phase peak current · 21 mm assumed slots, assumed N42SH magnets, four rotor positions, graded native 3-D grid. Measured shaft torque is increased by 1.8 N·m for electromagnetic torque. The separate 100° benchmark is not mixed into this curve.
Reference publication ↗EXACT RECORDED SAMPLES
Compare one operating point.
Only documented samples are compared. No interpolation. Percentage differences are not uncertainty bounds. The reference includes the 1.8 N·m shaft-to-electromagnetic torque adjustment.
View the plotted data
| Series | Phase current / A peak | Torque / N·m |
|---|---|---|
| Native 3-D · q axis | 101.6 | 57.3 |
| Native 3-D · q axis | 303.1 | 168.1 |
| Native 3-D · q axis | 505.2 | 270.9 |
| Native 3-D · q axis | 706.7 | 361.3 |
| Measured shaft + 1.8 N·m | 101.6 | 55.4 |
| Measured shaft + 1.8 N·m | 303.1 | 165.4 |
| Measured shaft + 1.8 N·m | 505.2 | 271 |
| Measured shaft + 1.8 N·m | 706.7 | 362.2 |
FIVE DOCUMENTED MACHINES
The reference notebook.
01Parviainen5 kW · 36 slots / 12 poles · TORUS-SIndependent-input EMF
GRADED-GRID COMPARISON
A low-speed machine with one rotor between two slotted stators and a full-pitch lap winding.
| Quantity | Model | Reference | Difference |
|---|---|---|---|
| Phase fundamental RMS EMF | 214.1 V | 211 V | ≈ +1.5% |
| Mean q-axis torque | 171.3 N·m | 169 N·m* | ≈ +1.4% |
Native 3-D · grid graded toward the iron · 300 rpm · magnets 100 °C. Torque at 8.4 A on the q axis. The ungraded grid read 214.9 V and 171.9 N·m.
Published geometry, turns and magnet data support an independent-input EMF comparison. The older section result was 242.8 V (+15%); that historical result used different modeling conditions, so it is not a controlled mesh-convergence series.
*169 N·m is inferred from measured EMF, not an independent shaft-torque measurement. The rated 159 N·m point has an unpublished current angle. Do not use the two torque references interchangeably.
A. Parviainen · LUT doctoral thesis, 2005 · Table 3.3 Publication ↗
Link to this reference ↗02Sahin30 kW · 24 slots / 4 poles · TORUS-SIndependent-input EMF
EMF & WINDING COMPARISONS
A high-speed flywheel machine with short-pitched lap windings and grain-oriented tape stators.
| Quantity | Model | Reference | Difference |
|---|---|---|---|
| Phase true RMS EMF / 1000 rpm | 12.84 V | 12.79 V | ≈ +0.4% |
| Phase fundamental / 1000 rpm | 12.76 V | 12.79 V* | ≈ −0.2% |
| Phase resistance · 26 °C | 20.5 mΩ | 20.2 mΩ | ≈ +1.4% |
Native 3-D · 1.3 mm as-built gap · both stators in series · magnets assumed at 25 °C. True RMS from the graded-grid benchmark; the fundamental and resistance rows are from a separate retained record.
Published turns, conductor and geometry support the comparison. Resistance also tests the modeled lap end turns. Both EMF conventions are shown because the measurement’s RMS convention is not stated.
*The same measured RMS reference is shown for both readings; it is not a separately measured fundamental. Bench magnet temperature is unpublished. Grain-oriented steel is modeled isotropically, so EMF agreement does not establish loss accuracy. The ungraded grid read 12.86 V (12.85 V in the benchmark registry).
F. Sahin · TU Eindhoven doctoral thesis, 2001 · Fig. 9.3 / Table 8.2 Publication ↗
Link to this reference ↗03Ghent · 4 kW16 poles / 15 slots · YASAEMF closure + thermal reference
EMF & THERMAL REFERENCES
A whole-machine YASA reference with shod teeth, also used to investigate heat paths and cooling assumptions.
| Quantity | Model | Reference | Difference |
|---|---|---|---|
| Phase fundamental RMS EMF | 126.9 V | 127.5 V | ≈ −0.5% |
| Winding · 100 W DC / 1000 rpm | 61.1 °C | 62.7 °C* | −1.6 K |
EMF: native 3-D · 2000 rpm · whole-machine 16-pole / 15-slot model. Temperature: lumped thermal network with slot-face cooling, not the 3-D EM solver.
The EMF is a closure check: winding turns were fitted to EMF on the section model. Agreement checks consistency of the reconstructed model, rather than independently predicting an unknown measured machine.
*Energies 11(11):2983, Table 3; documented thermal-network result with published support paths and no fitting. Another campaign reports 56.0 °C. Loaded magnet-temperature rises remain 60–85% low in documented cases. Winding-temperature agreement is not a blanket thermal-accuracy claim.
Vansompel / Hemeida / Sergeant and collaborators · Ghent reference-machine records
Link to this reference ↗04Abdelli · IFPEN18 slots / 12 poles · TORUS-S · ironless rotorLoaded torque + loss reference
TORQUE & NO-LOAD LOSS COMPARISONS
A high-current machine used to examine saturation and the gap between predicted and manufactured losses.
| Quantity | Model | Reference | Difference |
|---|---|---|---|
| Mean electromagnetic torque | 370.5 N·m | 362.2 N·m* | ≈ +2.3% |
| No-load EMF fundamental, peak | 37.60 V | 38.40 V | ≈ −2.1% |
| No-load loss · 4000 rpm | 984 W | 1260 W† | ≈ −21.9% |
| No-load loss · 6000 rpm | 2103 W | 2519 W† | ≈ −16.5% |
| No-load loss · 8000 rpm | 3649 W | 4175 W† | ≈ −12.6% |
Native 3-D · torque at 1000 rpm, approximately 707 A peak and 100° electrical. Loss rows are separate no-load speed sweeps, with magnets segmented 15 times radially.
The current–torque curve probes loaded saturation. The loss comparison exposes a remaining discrepancy: measured machined-stator losses are 14–28% above the model; stamped-stator losses are 75–100% above it, across the documented comparison range.
*Measured shaft torque is adjusted by the 1.8 N·m no-load torque to compare electromagnetic torque. †Machined stator; figure readings approximately ±2%. Differences here use (model − reference) / reference; the source’s ‘measurement above model’ uses a different denominator. Slot dimensions and magnet grade are partly assumed. Holder eddy currents and bearing/seal losses are not included.
Abdelli et al. · EPJ Web of Conferences 330:01003, 2025 (CISTEM 2024) · Figs. 11–12 Publication ↗
Link to this reference ↗05Ghent · 26p / 24s48 V · 26 poles / 24 slots · YASAResistance reference
DOCUMENTED WINDING CHECK
A measured stall-performance prototype with 35 turns per tooth and eight coils in series per phase.
| Quantity | Model | Reference | Difference |
|---|---|---|---|
| Phase resistance · 20 °C | 0.688 Ω | 0.742 Ω* | ≈ −7.3% |
Analytic winding-resistance model · published 0.8 mm copper wire · phase reference temperature-corrected from coil measurements at 25 °C.
This reference helped identify end-turn length errors. The current documented model is below the measured terminal resistance; terminal wire is included in the measurement and omitted from the model.
*Derived phase reference from measured coil resistance, not a separate 20 °C phase test. No measured EMF comparator is published. Magnet grade and arc are assumed; comparison against the paper’s analytical EMF is not experimental validation. This winding record is not a newly rerun result.
Van Damme, Vansompel & Crevecoeur · Machines 11(4):487, 2023 Publication ↗
Link to this reference ↗