HYDRAMECHANICAL PROTECTIVE SYSTEM
flyweights move out and push the speed sensing valve
Emergency Manual Shutoff
spool out to open and close passages to put oil pressure
into the correct system circuits. This gives correct
This shutoff is used under emergency conditions
protective system operation under the two engine oil
to shutdown the engine manually. When operated, this
shutoff simulates an engine overspeed condition in the
Thus, the air and fuel to the
combustion chambers is stopped. The shutoff is also
used to check the protective system for correct operation
at regular engine maintenance periods.
If there is a low oil pressure, high coolant
temperature or engine overspeed condition, the diverter
The emergency manual shutoff can be operated
valve moves to put system oil pressure in the fuel shutoff
at the engine or from a remote location. For remote
circuit. This moves the governor and fuel control linkage
operation, either air or electric power can be used.
to the "SHUTOFF" position to shutdown the engine.
Shutoff Control Group
Thermostatic Pilot Valve
This valve is used to feel engine coolant
temperature. If the coolant temperature goes above the
limit of the thermostatic pilot valve, the valve opens and
causes engine shutdown through the fuel shutoff circuit
of the protective system.
Water Temperature Contactor
The contactor switch for water temperature is
installed in the water manifold housing (below the
This is normally where the
thermostatic pilot valve is installed. No adjustment to the
temperature range of the contactor can be made. The
element feels the temperature of the coolant and then
operates a micro switch (in the contactor) when the
coolant temperature is too high. The element must be in
contact with the coolant to operate correctly. If the cause
for the engine being too hot is because of low coolant
level or no coolant, the contactor switch will not operate.
The switch is connected to an alarm system and
SHUTOFF CONTROL GROUP
activates an alarm under high coolant temperature
1. Spring for overspeed adjustment. 2. Emergency
conditions. When the temperature of the coolant lowers
manual shutoff valve. 3. Valve spool (not used). 4.
to the operating range, the contactor switch opens
Selector valve. 5. Speed sensing valve spool. 6.
Speeder spring. 7. Flyweights. 8. Low speed oil
protection valve. 9. High speed oil protection valve.
10. Oil pump. 11. Oil pressure relief valve. 12.
Pressure control valve group which consists of: the
fuel and air inlet sequence valves, the two-way pilot
operated valve and emergency manual shutoff valve
A flyweight controlled, speed sensing valve spool is used
to feel engine speed. The speed sensing valve spool is
moved by flyweights which are turned by a drive shaft.
The drive shaft is driven by the engine camshaft through
an accessory drive group that has an oil reservoir for the
WATER TEMPERATURE CONTACTOR SWITCH
shutoff system. When engine speed increases, the