Motion System Design

A gaggle of gearmotors

Most solar thermal installations built around a central tower are limited to research facilities — but Gemasolar, located in southern France, in conjunction with Nord Gear Corp., Waunakee, Wis., is now building a full-scale production site. In order to ensure precise and reliable operation of the plant's mobile heliostats that focus the sunlight, a vast array made up of 2,650 mirrors is being equipped with 5,300 gearmotors supplied by Nord.

The Gemasolar plant setup consists of a central tower with a receptor area at the top of the structure, a liquid circulation cycle including storage tanks and heat exchanger facilities for power generation, and an array of mirror units that focus solar rays onto the receiver. The mirrors are designed to turn and tilt, following the sun, to ensure that as much sunlight as possible is reflected onto the designated area of the tower. For each of the 2,650 flat mirror units, two NORDBLOC.1 gearmotors enable highly accurate movements for two axes to track the sun's path.

Gemasolar is the first commercial-scale concentrated solar power plant with central tower technology that implements a heat storage system based on molten salts. Liquefied nitrate salts are pumped up from a storage tank, run through the receiver section, and absorb the heat impact of the highly concentrated solar radiation in that tower segment. For more information, contact (608) 849-7300 or visit

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