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Illustration 1 g00290899
ETR Junction Box with oil pressure protection (OP) and water temperature protection (WT) that does not require a switchgear for use on 3200 through 3400 Engines
(1) Terminal strips (TS)
(2) Wiring harness
(3) Junction box
(4) Identification foil
(5) Jumper between terminals (TS-3) and (TS-4)
(6) Jumper between terminals (TS-4) and (TS-5)
(7) Jumper between terminals (TS-5) and (TS-6)
(8) Emergency stop switch (ES)
(9) Jumper between terminals (TS-28) and (TS-29)
(10) Jumper between terminals (TS-30) and (TS-31)
(11) Slave relay (SR1)
(12) Slave relay (SR2) for air shutoff solenoid (ASOS)
(13) Grommets for engine oil pressure switches
(14) Start/stop switch (SSS)
(15) Slave relay (SR3) for starting aid switch (if equipped)
(16) Circuit breakers
(17) Mounting brackets for grommets
(18) Engine oil pressure switch (OPS1) Introduction
The ETR Junction Box with oil pressure protection (OP) and water temperature protection (WT) that does not require a switchgear is a system that has full protection. The system has a junction box arrangement that is designed to monitor four functions:
Oil pressure
Coolant temperatureThe junction box includes the following components:
Start/stop switch (SSS) (14)
Slave relay (SR1) (11)
Slave relay (SR2) (12)
Oil pressure switch (OPS1) (18)
Emergency stop switch (ES) (8)The components that are listed below operate with the junction box. The components are also mounted on the engine.
Fuel shutoff solenoid (FSOS)
Water temperature switch (WTS)The slave relay (SR1) must be energized in order for the engine to run with the ETR electric protection system.An air shutoff solenoid (ASOS) is not used because the engine overspeed is not monitored.Note: If the customer installs a mechanical overspeed switch on the engine, remove the jumper between terminals (TS-3) and (TS-4) on the terminal strip of the junction box.Electrical Schematics and Wiring Diagrams
This manual contains the point-to-point wiring diagrams for the complete electric protection system and the junction box. Four types of electrical schematics for each electric protection system arrangement are shown in this service manual.
Junction box wiring diagram
IEC (International Electro-Technical Commission) schematic
JIC (Joint Industrial Council) schematic
Junction box wiring harness diagramNote: The line number that follows a component code gives the location of the component on the IEC and JIC schematics.Circuit Operation With No Faults
Engine Shutdown
When the engine is stopped, power is not available to any of the protection components. All switches are then in the normally open position or the normally closed position.Engine Start-up
Illustration 2 g00282739
5N-0364 Switch
(1) Keyway
Table 1
Switch Position Contacts that are closed
START (A) 1-2 and 4-5
RUN (B) 2-3 and 4-5
STOP (C) 2-3 and 5-6 A toggle switch is located on the front of the junction box. The switch is spring loaded and the toggle switch is automatically returned to the RUN. This happens when the toggle is manually released from the START position. This start/stop switch (SSS) has three positions:
START (A)
RUN (B)
STOP (C)When the start/stop switch (SSS) is moved to the START position, the following events should occur in the electric circuit.
The start/stop switch (SSS) closes the circuit to the starting motor.
The starter motor magnetic switch (SMMS) (line 9) closes a contact (line 3) which energizes the pinion solenoid (PS) (line 3).
The PS closes a contact (line 2) which energizes the starter motor (SM).
The current flows from terminal (TS-21) through the water temperature switch (WTS) (line 14).
The SSS closes across the contacts (SSS-4) (line 21) and (SSS-5) (line 20).
The current flows through contacts (SR2-30) and (SR2-87a) (line 28) of the slave relay (SR2). This energizes the slave relay (SR1).
Slave relay (SR1) closes contacts (SR1-30) and (SR1-87) (line 43) which are normally open.
The fuel solenoid (FS) is energized by the events in the circuit that is described above. The FS then allows fuel to flow to the engine. When the toggle of the start/stop switch is held in the START position, power is always available to the starter motor until the engine begins to run. When the engine begins to run, the crank terminate switch (CT) stops the current that runs to the starter motor. When the engine begins to run, move the start/stop switch to the RUN position. If the engine oil pressure is too low to open the oil pressure switch (OPS1), the contacts across terminals (OPS1-1) and (OPS1-3) (line 15) open after the 9 second time limit. The slave relay (SR1) (line 36) is energized and the engine will shut down. Refer to "Fault Circuit Operation" for the complete circuit description under these conditions.Note: If an electric starting motor is not used and an alternator is not used to run the engine, connect the power source to the engine. Connect the positive lead of the power source to terminal (TS-1) and connect the negative lead to terminal (TS-28) of the junction box. If an electric starting motor is not used and an alternator is used, the battery can still be used to run the engine. Connect the battery cables to the studs for the power input which are located on the bottom of the power distribution box.
To prevent engine damage after the engine is started, make sure normal oil pressure is observed on the engine oil pressure gauge. If oil pressure does not increase enough to open the contacts OPS1-1 and OPS1-2 of the oil pressure switch OPS1, the engine shutdown must be done manually.
Engine Mounted Start/Stop Switch (EMSS)
Illustration 3 g00281973
Engine mounted start/stop switch (typical example)
(1) OFF position with switch terminals (B) and (C) closed. (2) ON position with switch terminals (B) and (R) closed. (3) START position with switch terminals (B), (R), and (S) closed.
Some engines use an engine mounted start switch (EMSS). The EMSS replaces the start/stop switch (SSS) and the contact (line 3) for the starting motor magnetic switch (SMMS). If an engine mounted start/stop switch is provided on the engine to control the electric starting motor, the start/stop switch (SSS) will not be installed in the junction box.The EMSS is a start/stop switch which functions in the same manner as the SSS. When the lever of the EMSS moves to the START position, the pinion solenoid (PS) (line 3) is energized. The contacts (line 2) of the PS close. This energizes the starter motor (SM). The lever of the EMSS must remain in the START position until the oil pressure