Can an electrical slip ring support the nacelle's mechanical load?

The short answer

Do not assume it can. An electrical slip ring transfers electrical circuits across rotation; structural support is a separate function unless the exact unit is designed and rated for it. A wind-yaw assembly needs a documented mechanical bearing path for nacelle and rotor loads.

Separate internal bearings from external load capacity

A slip ring may contain bearings needed for its own rotor and stator alignment. Their presence does not establish permission to support an attached nacelle or absorb external shaft forces. Moog’s AC6023 instructions explicitly prohibit using that capsule to bear connected equipment weight and restrict external rotor loads. That is a product-specific example of why an electrical rotary joint is not automatically a structural bearing.

Trace loads around the rotary connection

Identify where nacelle weight, rotor thrust and tilting moments pass through the actual yaw support. Cable forces and mounting misalignment should also be included where they reach the slip ring. A correct current/voltage selection says nothing about those mechanical paths. If a combined structural/electrical assembly is proposed, request its integrated ratings rather than infer them from a conventional capsule’s electrical specification.

Request mechanical ratings with the electrical offer

Ask for permitted radial/axial forces, mounting arrangement, alignment conditions and the manufacturer’s statement of intended structural function. MARSTON slip-ring use is unconfirmed; electric yaw does not establish one is fitted. Do not hang external equipment from an unrated rotary joint or treat smooth rotation as proof of capacity. The concrete acceptance decision is whether structural loads bypass the electrical joint as designed, or are explicitly covered by a rated integrated assembly. If an integrated rotary assembly claims structural capacity, require the load reference and bearing boundary explicitly. The mere inclusion of electrical circuits in that assembly does not invalidate a genuine structural rating or establish one.