The mechanical centrifugal governor system
matching (SPM) synchronizer (7), and a master
backs up the ECU of the Woodward governor
frequency trimmer (8). Following is a list of these
system. The centrifugal governor speeder spring
eight components and a brief description of their
device takes over control if the ECU fails and the
functions. The items are keyed to figure 3-26.
engine speed increases due to the actuator
positioning itself for full-speed failure mode. It
1. The electronic fuel control regulates fuel
is set for about 62 Hz (depending on load) or the
during turbine lightoff, acceleration, and
equivalent speed of about 14,300 rpm. This is 480
60-Hz power generation. It monitors speed,
rpm above the 60-Hz speed of 13,821 rpm. The
TIT, and liquid fuel valve position.
centrifugal governor is part of the EG actuator
2. The LFV with the LVDT meters the fuel
assembly.
to the engine.
3. The EGB-2P actuator positions the LFV
MODEL 139 GOVERNOR SYSTEM
feeding the valve position back to the fuel
control through the LVDT.
The engine speed governor on the model 139
4. The Allison speed and temperature module
GTGS is the Woodward 9900-302 electrohydraulic
monitors the TIT and engine speed. It
control system. It also uses a backup centrifugal
supplies signals to the electronic fuel
governor override. There are eight components
control. This is for the start fuel schedule
within the system. These components are shown
and for maximum temperature control.
on figure 3-26, an interface diagram of the
5. The CIT sensor monitors the ambient air
Woodward 9900-302 governor. They are an
temperature. It applies the signal to the
electronic fuel control (1), an LFV with an LVDT
s p e e d correction and acceleration
(2), an EGB-2P actuator (3), an Allison speed and
temperature reference circuits.
6. The magnetic pickup senses turbine
temperature module (4), a CIT sensor (5), a
magnetic speed pickup (6), a speed phase
speed as an ac pulse signal with a
Figure 3-26.--Woodward 9900-302 governor interface diagram.
3-35
