AUTOMATIC START/STOP SYSTEM
SYSTEMS OPERATION
ELECTRIC SHUTOFF AND ALARM SYSTEM
INTRODUCTION
There are three types of electrical protection systems
available for the 3300 Generator Set Engines.
1.
Oil Pressure and Water Temperature Protection.
2.
Oil Pressure, Water Temperature and Over-
speed Protection.
3.
Automatic Start Stop Systems.
a.
Package Generator Set.
b.
Non-Package Generator Set.
This manual has information for No. I and 2. Make
reference to the Generator manual and the Switch-gear
manual for information for No. 3.
The electric shut-off system is designed to give
protection to the engine if there is a problem or a failure
in any of the different engine systems. The engine
systems that are monitored are: engine over-speed,
starter motor crank terminate, engine oil pressure and
engine coolant temperature.
The electric protection system consists of the electronic
speed switch and time delay relay. This system monitors
the engine from starting through rated speed.
Dual Speed Switch (DSS) The speed switch has
controls (in a single unit) to monitor engine over-speed
and crank terminate speed.
Engine Over-speed An adjustable engine speed setting
(normally 118% of rated speed) that gives protection to
the engine from damage if the engine runs too fast. This
condition will cause a switch to close that shuts off the
fuel to the engine.
Crank Terminate (Starter Motor) An adjustable engine
speed setting that gives protection to the starter motor
from damage by over-speed. This condition will cause a
switch to open that stops current flow to starter motor
circuit, and the starter motor pinion gear will then
disengage from engine flywheel ring gear. The crank
terminate can also be used to activate the time delay
relay.
Time Delay Relay This relay has special ON OFF
switches with two controls that will either make the relay
activate immediately, or after a 9 second delay. The time
delay relay is used to arm the shutdown system. The
time delay relay has a 70 second delay to be sure of
complete engine shutdown and to prevent damage to the
shutoff solenoids.
Water Temperature Contactor Switch This contactor
switch is a separate unit (mounted in the water manifold)
that is wired into the shutdown circuit. It has an element
that feels the temperature of the coolant (it must be in
contact with the coolant). When the engine coolant
temperature becomes too high, the switch closes to
cause the fuel to be shut off to the engine.
Engine Oil Pressure Switch This switch is mounted at
the rear of the engine and feels the pressure of the oil in
the oil manifold. The oil pressure switch is used to
determine low engine oil pressure and to activate the
time delay relay.
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