5 Phase Dual Axial Flux Permanent Magnet Generator Calculator
Estimate open-circuit RMS phase and line voltages from speed, active annulus, pole, and winding inputs for a dual-rotor five-phase AFPM generator.
From Permanent Magnet Data to the Air-Gap Flux Input
The calculator needs the peak fundamental axial flux density in the assembled air gap. Do not enter a magnet grade or its remanence value as that input: those describe the magnet material, while the field at the stator also depends on the magnetic circuit and operating geometry.
- Establish the field at the intended geometry. Use a magnetic model that represents both rotor faces, magnet coverage, back iron, stator, and air gaps, or use a traceable field measurement from an assembled prototype. Extract the fundamental axial field over the active annulus rather than substituting a magnet datasheet value.
- Match the model's annulus and winding inputs. Enter the active inner and outer diameters, pole count, turns per coil, total five-phase coil count, and a winding factor supported by the winding layout. The calculator assumes equal series-connected coil groups in a star connection.
- Treat the output as an open-circuit cross-check. Compare the estimate with a winding-aware model or a measured no-load waveform. This screen does not resolve the two air gaps, flux sharing, leakage, loaded voltage, power, losses, or temperature, and the second rotor is not an automatic multiplier.
If the assembled-gap fundamental field or winding factor is unknown, leave the estimate as a screening exercise and request an engineering review instead of inferring either value from magnet grade alone.
Key Design Insights for 5-Phase Dual Rotor Topologies
Fault tolerance depends on the drive design
A five-phase winding can support controlled operation after some open-circuit faults, but only with suitable current regulation and inverter topology. This calculator does not assess faulted operation or torque ripple.
Two distinct line voltages exist
For a balanced sinusoidal five-phase star connection, adjacent phases are 72° apart and non-adjacent phases are 144° apart, so their line-to-line RMS voltages differ.
Source: Derived from the balanced five-phase voltage phasors.
Dual-rotor geometry is not solved by this screen
The estimate uses the entered peak fundamental air-gap flux density over one active annulus. It does not model the two air gaps, leakage, magnet shape, or stator construction, and does not double area or voltage for two rotors.
Source: Model scope: this tool does not solve dual-gap field geometry.
Need a detailed winding-aware review of a 5-phase estimate? Share your coil layout, fault tolerance goals, and operating limits with the engineering team.
Request engineering reviewMethodology & Sources
| Source | Usage | Limitation |
|---|---|---|
| Asko Parviainen, Design of Axial-Flux Permanent-Magnet Low-Speed Machines and Performance Comparison between Radial-Flux and Axial-Flux Machines, §2.2.4 (2005)Reviewed: | Reference for fundamental no-load phase-voltage estimation from air-gap flux, series turns, frequency, and winding factor. This page uses the sinusoidal 4.44 f N Φ form. | This thesis models a different axial-flux topology. It supports the voltage equation only; this calculator simplifies the field to a uniform annulus and does not model leakage, loaded voltage drop, saturation, or harmonics. |
| Fault-tolerant operation for five-phase permanent-magnet synchronous machine drives with five-phase six-leg inverter (Wu et al., IET, 2024)Reviewed: | Evidence that degraded operation after open-circuit faults depends on current regulation and inverter topology. | This is a drive-system study, not a validation of this generator calculator or of any specific machine design. |
| Five-Phase Line Commutated Rectifiers, §2 (IntechOpen)Reviewed: | Reference for balanced five-phase phasors and the distinct adjacent and non-adjacent line-voltage ratios. | The chapter explains an ideal five-phase source and rectifier; it does not validate a generator winding or loaded operating point. |
Calculation basis
- Electrical frequency:
f = poles × RPM / 120. - Flux per pole:
Φ ≈ (2/π) × Bpeak × annulus area / poles, assuming a sinusoidal field over a uniform annulus. - Open-circuit phase voltage:
Ephase ≈ 4.44 × f × turns per phase × kw × Φ. The model assumes all entered coils are series-connected as equal groups across five phases. - Star-connected line voltage:
Vline = 2 × Vphase × sin(phase separation / 2). This gives 72° for adjacent phases and 144° for non-adjacent phases.
These are screening equations. Confirm the actual winding diagram, flux waveform, connection, insulation, current, thermal limits, and loaded voltage before selecting hardware. Default values are illustrative inputs, not measured test results or a generator rating.
The 400 Hz frequency and 1,000 V line-voltage alerts are this tool's screening triggers, not validated performance limits or compliance thresholds.
5-Phase Dual Axial Flux Permanent Magnet Generator FAQ
What does this 5-phase generator calculator estimate?
It estimates electrical frequency, open-circuit RMS phase voltage, and star-connected line voltages (adjacent and non-adjacent) from speed, active annulus dimensions, pole/coil counts, peak fundamental air-gap flux density, winding factor, and turns per coil. It does not predict loaded voltage or rated power.
Why does a 5-phase generator have two line voltages?
A 5-phase system has phases separated by 72 electrical degrees. Measuring voltage between adjacent phases (e.g., A and B) gives a different result than measuring between non-adjacent phases (e.g., A and C, separated by 144 degrees).
Is this calculator for coreless or iron-core stators?
It is a first-pass voltage screen for either construction if you supply a suitable peak fundamental air-gap flux density and winding factor. It does not model cogging torque, stator-core loss, magnet eddy-current loss, or winding temperature.
What does the pole-count and coil-count warning mean?
Equal pole and coil counts are not automatically invalid. The warning means this screening model cannot verify the actual coil layout, winding factor, back-EMF harmonics, or cogging torque; check the winding diagram before choosing a design.
Does this tool predict loaded voltage or rated power?
No. It estimates sinusoidal open-circuit voltage. Loaded voltage and continuous power also depend on current, winding resistance, leakage reactance, losses, cooling, and duty cycle, none of which this screen calculates.
Should I double the result because the generator has two rotors?
No. Enter the peak fundamental air-gap flux density for the active annulus used by the model. The calculator does not model two separate air gaps or add voltage for the second rotor; determine the actual magnetic circuit from the machine geometry or field analysis.
How should I choose flux density and winding factor?
Use values supported by a magnetic design, finite-element analysis, or measurement for the intended operating point. Magnet grade or remanence alone is not the air-gap fundamental flux density, and the winding factor depends on the actual coil layout and pitch.
Does five-phase operation guarantee fault-tolerant output?
No. Continuing operation after a phase fault depends on the fault type, winding isolation, inverter topology, current limits, and control strategy. This voltage screen does not quantify post-fault power or torque.
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