User guide

94
Pedestal
Elevation Gearbox
The elevation gearbox is a low backlash worm gearbox. The worm gear drive isolates any backlash in the motor drive from
the system. In addition, since it is a 30:1 ratio, it will not back drive eliminating any need for a brake on the drive train. The
motor drives the input worm via a quill/female hole and square key. The dual elevation drive shafts are driven with a square
key. The elevation capstan is secured to the dual output shafts with a cap screw that clamps to the output shaft. The
gearbox contains synthetic oil. Because of the design capacity of the gearbox, low rpm and comparative limited cycles
experienced by the system, no wear or maintenance is expected.
Elevation Motor
The elevation drive motor is a 24V DC motor with integral spur gear train. The motor armature rotates at up to 4000 rpm
causing a high frequency noise that will vary depending on the loading condition of the motor. An optical encoder is
mounted to the other end of the motor output shaft to provide real time positional information to the TracStar controller. The
maximum output speed is 133 rpm. The output shaft is a standard keyed shaft. The output torque capacity of the motor is
rated for the operational wind load. Since the low backlash worm gear drive isolates the backlash from the motor, any
backlash between the square key and motor gear train will never be seen by the reflector boresight. Any backlash at any of
these points is of no consequence to the system performance. No maintenance or wear of the elevation motor is expected.
Elevation Roto-Lok Cable Drive
The patented azimuth Roto-Lok drive produces a drive system with zero backlash, high stiffness, no wear, no lubrication,
and maximum reliability. The system consists of eight 1/16 9x17 stainless steel aircraft control cables, reverse-wrapped
three times around the capstan with solid connections on one end and high force, Belleville springs on the other end
occurring at the elevation cable termination block.
Four cables have the capacity to withstand an 80 mph wind load. The additional cables are used to provide increased
stiffness and drive redundancy. If a cable becomes damaged during usage, merely cut off the cable and continue to
use the positioner. You can replace the cable at your maintenance facility whenever time permits.
The cables are sized to last the life of the positioner. No replacement from wear is expected. The springs package at one
end will automatically compensate for any elongation of the cable. At installation, the Belleville springs are collapsed until
no "air" is seen between the springs. You should check this condition yearly to monitor the slow settling of the cable
strands.