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Engineering and manufacturing of electrical equipment and industrial automated systems
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The big wheel “London Eye”

Creation and implementation of all electrical equipment and automated systems for the 32 wheel’s capsules


Date of completion
British Airways London Eye ltd
Infrastructure - tourism


Customer stakes:

To realize the world's largest wheel

After 10 years of perseverance and passion, visionary architect David MARKS obtained permission to build the world’s largest wheel opposite Big Ben on the Thames. As for the deadline, the project must be completed in less than 18 months to allow an inauguration during the transition to the year 2000. The challenge is on!

Technical challenge:

A unique technological challenge

The 135-metre wheel weighs several hundred tons. Its structure, similar to a bicycle wheel, includes steel cables acting as spokes, whose tension is continuously measured by lasers.


The 32 capsules, 8 meters long and 4 meters in diameter, are located outside the wheel rim. This specificity requires regulating the inclination of their floor to within 0.1°, depending on the speed of the wheel and the position of the capsule.


Another peculiarity is that the power supply of the capsules turns out to be constraining. Ultra-equipped (air conditioning, fire detection, trim motorization, video, ambient sound system, RGB Led lighting…), they also rotate in relation to the rim which itself rotates in relation to the ground, making communication between the capsules automated systems and those on the ground complex.

The SEMER Solution:

Redundant automated systems to ensure safety functions and very high availability.

Two years of reflection with the architect and the partners of the POMA group and one year of construction were necessary to allow SEMER to ensure the complete design of the electrical control-command, communication and information equipment for the 32 capsules.


Each of them is considered as a flying object in its own right, which must be supplied with energy and whose position must be controlled.


As the evacuation of 1200 people is not possible, communication with passengers and their surveillance must be ensured continuously and centralized in a control tower.


A real performance in 2000, the 32 cabins are connected by Wi-Fi radio networks to the ground driving station, for video surveillance, intercom and control via industrial PLCs. To date, there are no flaws in the operation and the solutions implemented are still relevant. In view of the total success of this masterpiece, the authorization to operate the wheel 3 years before dismantling was increased to 99 years!

Key figures


4 , 5  

million people transported per year

Flight duration

2 0  

minutes at 135 meters high

Capsule’s size


meters long for 25 passengers