Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 1 Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas Engineering and Design Topics PM# February 2006

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 2 ► Technical Description Base Structure Azimuth BearingYoke StructureAZ Drive System Az & El Brake System Az & El hard Stops Az & El Stow PinsAz & El Cable Wrap HVAC System Feed Shutter KoM design Design Progress

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 3 Base Structure ► Technical Description In the following figures we report the new layout of the Base structure. The main changes are related to the optimization of the following subassembly. 1)Az drive position 2)Az bearing dimensions 3)Az brake system 4)Az brake general layout During this phase we have considered also the possibility to improve structural behaviour. FEM analysis and FEM optimization will follow in order to the thicknesses and general geometry Old Base Structure Progress design of Base Structure

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 4 Azimuth Bearing ► Technical Description The bearing, is a three-roller bearing. We have changed the design and dimensions of the bearing in order to: change the position of the AZ drive and Az brake improve the stiffness requirements and forces distribution

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 5 Yoke Structure ► Technical Description In the following figures we report the new layout of yoke structure. The main changes are related to the optimization of the following subassembly. 1)Az drive position 2)Az bearing dimensions 3)Az brake system 4)Az brake general layout During this phase we have considered also the possibility to improve structural behaviour. FEM analysis and FEM optimization will follow in order to the thicknesses and general geometry

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 6 Azimuth Drive ► Technical Description Azimuth Motor description The Azimuth Motor Drive system has been installed outside of the base. The wound part is mounted on the antenna yoke while the magnet disk is bolted directly to the Azimuth base. With the new configuration the motor have the needed torque for the acceleration requirements and the design is able to satisfy the LRU requirements.

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 7 Azimuth & Elevation Hard Stops ► Technical Description Definition of position of the Az and EL Hard Stop:

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 8 Azimuth & Elevation Stow Pins ► Technical Description Definition of position of the Az and EL Stow Pins: Azimuth Stow Pins Elevation Stow Pins

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 9 Azimuth & Elevation Cable Wrap ► Technical Description The AZIMUTH CABLE WRAP has been totally re- designed. In the figure below is indicated the new design. The ELEVATION CABLE DRAPES reflects the prototype solution, but with some improvement and optimization.

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 10 With the new position of the Az motor system, we don’t need a cooling system inside the base of the Antenna. The total power of the HVAC system will be 30% less than for the prototype HVAC System ► Technical Description

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 11 Azimuth & Elevation Brake System ► Technical Description In the new design of the base, the Azimuth Brake is now inside the base. Due to a reduction of the diameter of the brake disk we need to increase the acting force of the calipers or add two more calipes. The Azimuth system foresees No. 2 or 4 calipers fixed to the yoke structure and acting on a ring connected to the base structure. The elevation system is constituted of No.2 calipers assembled on the yoke structure that act on the track assembled on the receiver cabin. The second caliper was added for redundancy and also to guarantee the absorption of the full drive torque. Azimuth Brake Prototype Azimuth Brake Production

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 12 Feed Shutter ► Technical Description The Feed Shutter is under review in order to guarantee the LRU requirements. A manual override is located in the cabin. A lock-out/ Tag- out will be added. Status sensor must report the Feed Shutter status to the Antenna Control Unit (ACU). The system will be automatically closed by a hardware limit switch when elevation is larger than 89 degrees. The open/close duration will be less than 30 sec.