Operation and Maintenance Manual

2
1.4.2 Azimuth Unit
The Azimuth Unit turns the Positioner through the horizontal plane. It is
designed to handle vertical and radial loads. The mechanism of the
Azimuth Unit is as follows: A DC motor drives a reduction worm gear
through a timing belt. The pinion on the reduction gear drives an internal
gear, which is an integral part of a slewing bearing assembly. The internal
gear drives the turntable, which carries the Elevation unit.
1.5 Electromechanical Sub-Assemblies
1.5.1 Limit Switches
The limit switches are designed to coordinate the rotation of the El axis.
The limit switches are of the electric rotary cam type. Each limit switch
assembly has two cams, one for UP and one for DOWN. The limit
switches are normally open.