Final Calibration Of System; Section 3- Azimuth Positioning System; Azimuth Bearing; Azimuth Gearbox - Patriot 1.2M MVSAT Installation & Assembly Instructions Manual

Table of Contents

2.5 CONTROLLER/POSITIONER VERIFICATION TEST CONT.

Watch reflector surface approach feed horn.

Press STOP when reflector is within 2" of feed horn.

Jog down until reflector presses on rubber padding on feed housing.

Adjust stow limit switch if necessary by bending lever. Stow switch is on east side with long lever. (East is the left

side as viewed from behind the reflector)

2.6 FINAL CALIBRATION OF SYSTEM

Check AZ ZERO position on roof. If azimuth controller will stow at AZ = 0.0 degrees you may adjust AZ zero

voltage +/- 2º to bias stow position. Adjust zero voltage per Section 4.1.1 of controller manual.

The azimuth bearings are precision ground sealed bearings with a dynamic and static moment capacity of over

four times the worst-case wind load specification. They are located on the AZ/EL casting top and bottom. The

bearing is packed with synthetic grease during assembly and no further greasing is required.

Because of the excess capacity, low rpm, and low number of cycles, no maintenance is required.

The azimuth gearbox is a low backlash worm gear box. The worm gear drive isolates any backlash in the motor

drive from the system. In addition, since it is a 40:1 ratio it will not back drive, eliminating any need for a brake on

the drive train. (See Fig.)

The motor drives the input worm via a quill/female

hole and square key. The worm shaft is extended

with a hex shape installed for the hand crank. The

azimuth capstan is secured to the output shaft with a

square key knurl plus permanent locktite to eliminate

any backlash between the capstan and gearbox.

The low backlash is achieved by selective fit of the

worm and worm gear. The nominal backlash for the

gearbox is 30' which is reduced by the Roto-Lok

drive to less than 4'of the beam of the antenna. The

gearbox contains synthetic oil filled half way to the

level plugs. Because of the design capacity of the

gearbox, low rpm and limited cycles experienced by

an SNG system, no maintenance is required.

Table of Contents