LOCATION AND DESCRIPTION OF MAJOR COMPONENTS (cont)
(2) During normal operation, the main transmission drives the shaft driven compressor, the accessory
drive lubrication pump, two ac generators, two hydraulic pumps, tail rotor output shaft, and the main rotor drive
(a) The shaft driven compressor draws ambient air through the particle separator. It is a single stage
centrifugal compressor driven by the left generator spur gear.
(b) Two ac generators are mounted on spur gears, one on either side of the main transmission housing,
which provide ac electrical power for the helicopter.
(c) Two hydraulic pumps pressurize the primary and utility hydraulic systems.
c. IGB Assembly.
The IGB assembly (fig. 64) connects the main transmission to the TGB. The gearbox
housing, mounted at the base of the vertical stabilizer, is finned for cooling. The housing assembly receives power
from drive shaft 5 and supplies power to drive shaft 6. The IGB assembly consists of four theremistors, an
accelerometer, a breather vent, and a cooling fan.
(1) Four temperature thermistors (sensors) are springloaded to maintain constant contact with the
(2) The accelerometer monitors vibration inside the IGB and is installed on the upper rear center section of
(3) The breather vent prevents the IGB housing from being overpressurized. It is filled with curled steel
mesh to provide a filter and is installed top of the housing assembly.
(4) The cooling fan and coupling assembly are mounted on the IGB input flange assembly. The cooling
fan maintains the IGB assembly at normal operating temperature
DRIVE SHAFT 6
DRIVE SHAFT 5