Technology / Engineering guide
Single-Phase & Three-Phase Wind Power Interfaces
Single-phase or three-phase is an interface description, not a complete wind-system specification. Identify whether the term refers to the generator, the converter output or the site’s load supply. Then check the voltage basis and configuration information at that exact boundary.
Name the interface before comparing the phase count.
Keep machine-side characteristics, converted output and the site supply requirement in separate records.
01 / Three boundaries
Separate machine, converter and site descriptions.
A generator description concerns the machine’s electrical output.
A generator description concerns the machine’s electrical output. A converter-output description concerns the selected equipment’s delivered interface. A site description concerns the supply available to, or required by, the loads. One boundary’s phase count does not automatically define the others.
Record each boundary on the project diagram using the actual equipment identity. A proposed conversion stage may change the form of supply, but its permitted input and output must come from its documentation. Do not infer a particular phase count for any MARSTON model from its rated power.
02 / Voltage basis
Distinguish phase-to-neutral and phase-to-phase values.
Three-phase quantities can be stated between two phases or between a phase and an applicable neutral point.
Three-phase quantities can be stated between two phases or between a phase and an applicable neutral point. A voltage without its measurement basis is incomplete. Retain whether a value is RMS or another stated quantity and the conditions under which it applies.
For a balanced sinusoidal star example, VLL = √3 × VLN. This conditional relationship is basic electrical science, not a MARSTON rating or connection instruction. It should not be applied blindly to an unspecified generator configuration, distorted waveform or different reference basis.
03 / Neutral scope
Do not assume a usable neutral from a phase label.
The phrase “three-phase” does not by itself establish an available neutral conductor or a permitted phase-to-neutral load interface.
The phrase “three-phase” does not by itself establish an available neutral conductor or a permitted phase-to-neutral load interface. Use the actual interface documents to identify what is provided and what loads the selected configuration supports.
Keep neutral availability, earthing arrangements and protective requirements as separate project topics. This page does not instruct changes to star or delta connections, create a neutral point or prescribe wiring. Those decisions belong to the responsible electrical designer and applicable equipment information.
04 / Load requirement
Describe what the loads actually need.
List loads by their required interface, power basis and relevant operating conditions.
List loads by their required interface, power basis and relevant operating conditions. A site containing single-phase loads and a three-phase motor needs more detail than a total-kilowatt figure. The load-profile guide helps retain demand timing.
Where a proposal has several phases, identify how the load allocation and its variations are assessed. An aggregate output rating is not sufficient evidence for every uneven load condition. Motor-starting requirements also need their own applicable information, rather than an assumption based on phase count.
05 / Ratings comparison
Use the same power and operating basis.
Keep active power in kW separate from apparent-power information and per-phase quantities.
Keep active power in kW separate from apparent-power information and per-phase quantities. Identify whether a rating applies to the total equipment or an individual path, and retain its voltage, frequency and operating conditions.
The five confirmed MARSTON turbine ratings are 5, 10, 20, 30 and 50 kW. These model ratings do not establish standard output voltages, phase configurations or direct suitability for a particular site supply. The selected controller and converter require an independent interface match.
06 / Interface handover
Preserve the boundary information in the enquiry.
A useful handover names the generator interface, converter input, converter output and site load interface, with their phase descriptions and voltage definitions.
A useful handover names the generator interface, converter input, converter output and site load interface, with their phase descriptions and voltage definitions. Include the diagrams and equipment versions from which those descriptions were taken.
Use the electrical interface guide for the broader connection schedule. Resolve any undefined phase, neutral or voltage basis before treating the proposal as compatible. No rewiring option or universal single-phase/three-phase conversion capability is promised here.
Continue the review with 50 Hz & 60 Hz Requirements for Wind Power Projects.
Continue the review with Grid-Following & Grid-Forming Wind Converters.
Continue the review with Small Wind Installer & System Integrator Selection.
For an additional three-phase quantity review, see phase imbalance and symmetrical components.
Review active, reactive and apparent power and CT ratios and meter scaling with the documented phase arrangement.
General background: US Department of Energy Electrical Science handbook: three-phase quantity definitions. These references explain industry concepts; they are separate from the applicable MARSTON product and project documents.
Prepare the information for this review.
Use the checklist to organise the project information. Mark unavailable items and retain document references.
| Review item | Information to provide | Purpose |
|---|---|---|
| Boundary identity | Generator, converter input, converter output or load supply | Locate each phase description. |
| Voltage definition | Phase-to-phase or phase-to-neutral, quantity and conditions | Compare like measurements. |
| Neutral availability | Documented interface and permitted load use | Avoid assuming an accessible neutral. |
| Load allocation | Actual load interfaces, timing and phase distribution | Define the service being assessed. |
| Rating basis | Total or per-path power with voltage and frequency context | Prevent incompatible comparisons. |
Engineering questions.
Does a three-phase generator mean a three-phase site output?
Not automatically. The selected conversion equipment determines its own documented output interface.
Can kW alone establish whether a load interface is suitable?
No. Phase configuration, voltage, frequency and relevant operating conditions also matter.
Is line-to-line voltage the same as phase-to-neutral voltage?
No. Their relationship depends on the configuration and waveform conditions.
Does a three-phase label guarantee an available neutral?
No. Confirm neutral availability and permitted use from the actual interface information.
Are the five MARSTON models confirmed for one standard phase configuration?
No common phase configuration or standard output voltage is established here.
What information helps resolve a phase-interface question?
The actual equipment diagram, boundary identity, voltage basis, output requirements and connected load descriptions.
Technical enquiry
Bring your project information to the discussion.
Single-phase or three-phase is an interface description, not a complete wind-system specification. Share the available information and the equipment scope you want reviewed in a technical quotation.