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 MAIN AXES DRIVES PM# July 2006

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 2 Antenna Drives Solution Linear Direct Drives Motors Performances: (*) Corresponding “ to drive the antennas to stow in a rainfall rate of 2 cm/hr, with a snow accumulation of 50kg/m 2 in the reflector…” (**) Corresponding “ to drive the antennas to stow in a rainfall rate of 2 cm/hr, with a snow accumulation of 41kg/m 2 in the reflector…” AXEST MAX requested by SPET MAX provided by motor Azimuth Nm Elevation Nm (*) Nm (**)

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 3 AZIMUTH LINEAR MOTOR – DIMENSIONING OPTIMIZATION UPDATE DESIGN LINES 1.Axial room increased up to 320° 2.Increase of sector dimension 3.Reduction of sectors quantity 4.Drive amplifiers on board 5.AC/DC power supply on cabinet 6.Increase of protection degree IP w.r.t. Prototype

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 4 ELEVATION LINEAR MOTOR – DIMENSIONING OPTIMIZATION UPDATE DESIGN LINES 1.Lateral room increased up to 49° 2.Increase of sector dimension 3.Reduction of sectors quantity 4.Drive amplifiers on board 5.AC/DC power supply on cabinet

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 5 Main implementations in order to increase torque performances Optimization of wiring (losses reduction) Analysis of possible substitution of PTC sensors system Increase of IP protection degree on AZ axis Optimized electronic solution (Drive on board) with Only DC bus from power supply unit (on switchboard) to sectors Reduction of EMC and harmonics/resonances (possible over-voltages disturbances) Increase availability of system

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 6 OPEN POINTS Maximum available EL torque Sectors handlings, in particular for EL Erection attachment points on EL axis, under analysis