Three rotating LED layers, engineered as a public landmark

An outdoor P4 installation in Xi’an with three independently servo-driven layers — where continuous rotation, wind exposure and a foundation interface all sit inside one engineering boundary.

Project at a glance

Delivered: March 2026
Location: Xi’an, China
Display size: 6.27 × 4.8 m
Display spec: Outdoor P4
Layers: 3, independently servo-driven
Drive: 1500 W servo per layer
Structure: Galvanised Q235B steel

Three-layer outdoor rotating LED tower installed beside a building in Xi'an by joeqing — The installed landmark. Three layers rotate independently on a central shaft.

The brief: outdoor rotation changes every boundary

Take a rotating LED tower outdoors and almost nothing carries over unchanged. Wind exposure becomes a structural case. Power and signal have to cross a continuously rotating joint. Corrosion protection stops being a finish and becomes a specification. Maintenance access has to work at height, outdoors, on a structure that turns.

None of those are display problems. They are the reason an outdoor kinetic landmark is engineered against the actual site rather than selected from a catalogue.

Structure, rotation, power path and service access share one project boundary. Solve them separately and they collide on site.

What was engineered

Structure

The reference build uses a galvanised Q235B steel framework with a central shaft and fabricated flanges, on a project-defined supporting structure. Galvanising is not cosmetic here — an outdoor rotating assembly cannot be taken down easily for remedial work.

Independent servo-driven rotation

Each of the three layers rotates on its own 1500 W servo, following the approved synchronised, counter-rotating or offset sequence. Reference position accuracy is ±0.1 mm with a control update of under 20 ms — the numbers that decide whether a multi-layer composition holds together or drifts.

Continuous rotating power transfer

A custom slip-ring route carries power and signal across the rotating boundary. Continuous rotation rules out any cable-managed solution: the joint has to work indefinitely, outdoors, without a service interval that requires shutting the landmark down.

Wind, foundation and access

Wind pressure, extreme weather, seismic conditions, foundation capacity, display weight, rotational inertia, braking and maintenance access are reviewed together, not in sequence. Rotational inertia in particular is easy to underestimate — it drives both the drive sizing and the braking case.

Reference value	Figure
Overall display size	6.27 × 4.8 m
Display specification	Outdoor P4
Rotating layers	3, independently controlled
Drive per layer	1500 W servo
Position accuracy	±0.1 mm
Control update	Under 20 ms
Framework	Galvanised Q235B steel, central shaft and fabricated flanges

Reference values from this configuration. Final figures are engineered against the actual site, wind-design basis and installation method.

Three-layer outdoor rotating LED tower as a public landmark in Xian by joeqing — The same installation read as a public landmark from the street.

Delivery

Foundation interface and service access are confirmed early, because both are expensive to change once steel is fabricated. The final landmark is engineered against the real site conditions rather than against a standard drawing.

Questions this project usually raises

What wind design basis do you need?

The local wind pressure and extreme weather data for the site, alongside seismic conditions and foundation capacity. Those four inputs, with display weight and rotational inertia, set the structural case before any drive specification is fixed.

How does power reach a continuously rotating display?

Through a custom slip-ring route that carries power and signal across the rotating boundary. Continuous rotation rules out cable-managed alternatives, so the joint is engineered to run indefinitely outdoors.

Can the layers rotate in opposite directions?

Yes. Each layer is independently servo-driven and can follow a synchronised, counter-rotating or offset sequence according to the approved programme.

Why galvanised steel rather than a painted finish?

Because an outdoor rotating assembly cannot easily be taken down for remedial work. Corrosion protection is treated as a specification with a service life, not as a surface finish.

Planning an outdoor moving landmark?

Send the location, target size, wind-design basis, support concept and LED scope. Engineering replies within 8 business hours.

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