United Technologies Carrier Transicold 69UG15, Operation And Service

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2–15 T-360
2.8 SAFETY DEVICES
Safety devices, such as circuit breakers, fuses, and safety switches protect system components from damage.
The AC generator, solid state battery charger, fuel heater, high water temperature, safety relay, total time meter
and intake heater are protected by circuit breakers. If a safety device opens and there is an interruption of electrical
current, the electronic governor module will be de-energized, which will also de-energize the fuel solenoid, interrupt
the fuel flow to the engine and stop the engine.
In units with auto restart, the engine, engine control devices, and engine monitoring devices are protected by the
auto restart module, low coolant sensor (if equipped), circuit breaker, low oil pressure switch, and high water tem-
perature switch. These safety devices monitor system operating conditions and open a set of electrical contacts
when an unsafe condition occurs. If a safety device opens and there is an interruption of electrical current, the elec-
tronic governor module will be de-energized, which will also de-energize the fuel solenoid, interrupt the fuel flow to
the engine and stop the engine.
De-energizing the fuel solenoid shuts off the fuel supply to the engine; thus stopping the engine. Safety device
specifications are provided in
Table 2–3 .
Table 2–3 Safety Devices
ENGINE
Unsafe Condition: Low engine lubricating oil pressure
Safety Switch Low oil pressure switch (LOP) - Automatic reset
Switch Setting Opens below 18 psig (1.27 kg/cm)
Unsafe Condition: High engine cooling water temperature
Safety Switch Water temperature switch (HWT) - Automatic reset
Switch Setting Opens at 230F (110
°
C)
Unsafe Condition: Excessive current draw by the safety relay, fuel heater, water temperature gauge, oil pressure gauge
or total time meter
Safety Switch Circuit breaker (CB-2) - Automatic reset
Switch Setting Trips at 30 amps
Unsafe Condition: Excessive current draw by the electronic governor module
Safety Switch Fuse 1, 2, 3 (replace)
Switch Setting Trips at 10 amps
INTAKE HEATER
Unsafe Condition: Excessive current draw on intake heater circuit
Safety Switch Circuit breaker (CB-3) - Automatic reset
Switch Setting Trips at 50 amps
BATTERY CHARGER
Unsafe Condition: Excessive current draw on 12 volt supply circuit.
Safety Switch Circuit breaker (CB-4) - Automatic reset
Switch Setting Trips at 50 amps
Unsafe Condition: Excessive current draw on 460 volt feed circuit
Safety Switch Fuses BCF3, BCF4, BCF5 (replace)
Switch Setting Trips at 5 amps