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ENGINEERING / REFERENCE REGISTER

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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.

Comparison coverage in this register · evidence types, not pass/fail verdicts
MachineBack-EMFTorqueNo-load lossHeatingResistance
ParviainenIndependent inputs Derived target Not in this registerNot in this registerNot in this register
SahinIndependent inputs Not in this registerNot in this registerNot in this registerDevelopment check
Ghent · 4 kWFitted closure Not in this registerNot in this registerPrescribed heating Not in this register
Abdelli · IFPENConditional inputs Adjusted measurement Measured comparison Not in this registerNot in this register
Ghent · 26p / 24sNot in this registerNot in this registerNot in this registerNot in this registerDerived 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 ↗
Scroll sideways for the full chart →Torque / N·m00100200200400300600400800 Native 3-D · q axis: 57.3 N·m at 101.6 A peakNative 3-D · q axis: 168.1 N·m at 303.1 A peakNative 3-D · q axis: 270.9 N·m at 505.2 A peakNative 3-D · q axis: 361.3 N·m at 706.7 A peak Measured shaft + 1.8 N·m: 55.4 N·m at 101.6 A peakMeasured shaft + 1.8 N·m: 165.4 N·m at 303.1 A peakMeasured shaft + 1.8 N·m: 271 N·m at 505.2 A peakMeasured shaft + 1.8 N·m: 362.2 N·m at 706.7 A peakPhase current / A peak
Native 3-D · q axisMeasured shaft + 1.8 N·m (dashed)
Look closer: the difference(model − reference) / reference · not an uncertainty bound
Phase peak current−4%0+4%Difference
101.6 A
+3.43%
303.1 A
+1.63%
505.2 A
-0.04%
706.7 A
-0.25%

EXACT RECORDED SAMPLES

Compare one operating point.

Native 3-D · q axis57.3 N·mModel prediction
Measured shaft + 1.8 N·m55.4 N·m+3.43% model − reference, relative to reference

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.

Recorded comparisons · conditions stay with the data
View the plotted data
Loaded torque at 1000 rpm · documented samples
SeriesPhase current / A peakTorque / N·m
Native 3-D · q axis101.657.3
Native 3-D · q axis303.1168.1
Native 3-D · q axis505.2270.9
Native 3-D · q axis706.7361.3
Measured shaft + 1.8 N·m101.655.4
Measured shaft + 1.8 N·m303.1165.4
Measured shaft + 1.8 N·m505.2271
Measured shaft + 1.8 N·m706.7362.2

FIVE DOCUMENTED MACHINES

The reference notebook.

Download the evidence register ↗
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.

Parviainen · documented comparisons
QuantityModelReferenceDifference
Phase fundamental RMS EMF214.1 V211 V≈ +1.5%
Mean q-axis torque171.3 N·m169 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.

Sahin · documented comparisons
QuantityModelReferenceDifference
Phase true RMS EMF / 1000 rpm12.84 V12.79 V≈ +0.4%
Phase fundamental / 1000 rpm12.76 V12.79 V*≈ −0.2%
Phase resistance · 26 °C20.5 mΩ20.2 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.

Ghent · 4 kW · documented comparisons
QuantityModelReferenceDifference
Phase fundamental RMS EMF126.9 V127.5 V≈ −0.5%
Winding · 100 W DC / 1000 rpm61.1 °C62.7 °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.

Abdelli · IFPEN · documented comparisons
QuantityModelReferenceDifference
Mean electromagnetic torque370.5 N·m362.2 N·m*≈ +2.3%
No-load EMF fundamental, peak37.60 V38.40 V≈ −2.1%
No-load loss · 4000 rpm984 W1260 W†≈ −21.9%
No-load loss · 6000 rpm2103 W2519 W†≈ −16.5%
No-load loss · 8000 rpm3649 W4175 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.

Ghent · 26p / 24s · documented comparisons
QuantityModelReferenceDifference
Phase resistance · 20 °C0.688 Ω0.742 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 ↗