Pressure at this point is regulated at 25 psig by
GTGS REDUCTION GEAR AND
excess flow returning to the reduction gear sump.
LUBE OIL SYSTEM
Oil to the engine and PTO assembly is regulated
to 15 psig.
The reduction gears used to couple the engine
Oil to the PTO assembly is directed by a nozzle
to the generator on the four models of GTGSs
onto the shaft coupling. It is then returned by
are identical. The reduction gear is a single-
gravity to the sump. The shaft mid-bearing is
reduction, single-helical gear type of speed
lubricated by a spray nozzle on the front of the
reducer. The reduction ratio is 7.678 to 1. The
compressor extension shaft housing. Oil to the
gear is an over-under, vertically offset, parallel
reduction gear assembly, 30 gpm at 25 psig,
shaft design. It uses a three-piece housing split
horizontally at the center lines of the high-speed
returns by gravity to the sump.
shaft and the low-speed shaft. The gear elements
are supported in sleeve bearings. The starter is
mounted on the gear case and drives the high-
POWER TAKE-OFF ASSEMBLY
speed shaft. The oil pump is located on the engine
side of the low-speed shaft. The reduction gear
The PTO assembly (fig. 3-23) has a PTO
is coupled to the generator by a diaphragm-type
shaft, shaft adapter, tapered coupling, mid-
flexible coupling.
bearing assembly, housing, and speed sensor
Refer to figure 3-21 to help you understand
pickup. The assembly transmits the torque
the following discussion of the reduction gear's
produced by the engine to the reduction gear. It
lube oil system. The lube oil system is a wet sump,
also provides the means to measure the engine
force-feed system. The sump has a capacity of 60
speed using a magnetic pickup mounted on the
gallons. It is an integral part of the reduction gear
housing over the shaft exciter wheel teeth.
assembly. It also serves as the supply tank for the
GTE lube oil system. Oil from the sump is picked
POWER TAKE-OFF SHAFT AND
up by the reduction gear supply pump (8). The
ADAPTER
pump is rated at 40 gpm at 1800 rpm. From the
pump, the oil passes through a 25-micron base-
The PTO shaft is a solid steel shaft. It is bolted
mounted filter (9) and through a remotely
to the shaft adapter at the forward end and splined
mounted oil cooler (10). It is then distributed to
to the compressor extension shaft at the aft end.
the reduction gear, PTO assembly, and the engine.
Figure 3-23.--PTO assembly.
3-30
