FUNCTIONING OF EQUIPMENT
Elevator Hoist. The electrical system for the
6-1 SCOPE. This chapter provides the theory of
elevator hoist is made up of a 20-ampere circuit breaker
operation for the Antenna Tower TS-9A and is directed
located in the junction box; a drum switch located on a
to those items comprising the electrical system.
lower tower leg; the electric hoist assembly; and a limit
Information is supplied for use by direct support, general
switch. A flexible hoist cable supplies power to the
support, and depot maintenance level personnel.
terminals in the hoist. The hoist control (drum switch)
that is connected to the terminals in the motor assembly
6-2 ELECTRICAL SYSTEM.
switch that controls the raising and lowering of the
entrance junction box which receives 115-Vac, 60-Hz,
antenna elevator. When the UP button is depressed,
primary power from an external power source. The
the elevator is raised; when the DOWN button is
junction box contains a terminal board and four
depressed, the elevator is lowered. The electric brake
individual circuit breakers to which this power is applied
in the hoist assembly holds the load when the buttons
for distribution. The individual circuit breakers distribute
are not depressed. The limit switch is a normally closed
the power through raceways to the aviation lighting
push switch physically located at the top of the tower
system, the electric hoist, and the two ac convenience
track and electrically connected by a limit switch cable
to terminals in the hoist assembly. When the elevator
reaches its uppermost limit of travel, it activates the
a. Aviation Lights. The electrical system for the
switch, causing it to break contact by opening the circuit
aviation lights is made up of a 15-ampere circuit breaker
and stopping hoist operation.
located in the junction box; a lighting control box located
on a lower tower leg; a junction box and two double
c. Convenience Outlets.
obstruction lights located near the tower top; wire leads;
electrical system provides two ac convenience outlets,
and rigid conduit and fittings. The power distributed by
each protected by a 15-ampere circuit breaker located in
the circuit breaker is applied to the input of the lighting
the junction box. One convenience outlet is located on
control unit. The three-lead output of the lighting control
a tower leg at the top of the tower. It obtains its power
unit supplies power to the tower top junction box, and in
from leads connected to one circuit breaker in the
turn to the two double obstruction lights. A switch is
junction box. The other convenience outlet is located on
located on the lighting control unit for manually turning
the junction box on a tower leg near the base of the
the aviation lights on and off. The lighting control unit
tower. It obtains its power from leads connected to a
has another output for connection to an alarm which
second circuit breaker in the junction box.
indicates failure in the aircraft lighting system.