TURBOCHARGER ASSEMBLY 3S4424 - Caterpillar

Pressure Switch
Illustration 2 g00763777
The switch is mounted in the passage that is connected to the main oil galley. When the pressure reaches 9 3 kPa, the switch closes and the "SOSR" relay is energized. The "Starting Oil Pressure Lamp" turns on and the engine is allowed to start.Liquid Detector Gp
Illustration 3 g00763726
The switch is an electronic sensor that detects the presence of oil. If oil is present, the output of the switch is ON, and the "SOSR" relay is energized. The "Starting Oil Pressure Lamp" turns on and the engine is allowed to start.Pressure Sender
Illustration 4 g00763715
The pressure sender varies resistance with pressure. The variable resistance is used in order to drive the "Air Start Gauge".Oil Level Switch
The switch provides an alarm signal if the oil level is too low in the oil pan. The switch is wired in the normally open position. A normal water level in the expansion tank holds the contacts of the switch closed. If the oil level falls and the contacts break, the I:3.0/0 input of the PLC becomes inactive. An alarm is then generated.Speed Sensor for the Turbocharger
The turbocharger speed sensor is used in order to measure the rotational speed of the turbocharger in RPM. The speed is monitored and an alarm is generated when the speed of the turbocharger exceeds 35000 RPM.
Table 1
Model     Number of Pulses per Revolution    
VTC254 straight inlet     1    
VTC254 90° inlet     2    
TPL61     2    
NA297 G     9    
NA297 GS     13    Speed Sensor
Illustration 5 g00763729
The turbocharger may have a speed sensor that is installed. When the correct number of pulses/revolution is configured into the PLC, the PLC will convert the pulse that is generated by the blade pass into the RPM for the turbocharger.Speed Sensor with Straight Inlet or with Silencer
This sensor is optional. The sensor detects the speed of the turbocharger from a magnet that is mounted in a cone on the shaft of the turbocharger.Speed Sensor with 90° Inlet
Illustration 6 g00763728
This sensor is optional. The sensor detects the speed of the turbocharger from a slot on a bolt that is mounted on the turbocharger.Optional Components
Rotary Sensor
Illustration 7 g00763722
The sensor is tied to the fuel control housing through a linkage. Movement of the fuel control linkage is converted into an electrical signal. The signal is amplified to a 4-20 mA signal that is proportional to the position of the rack of the engine. Refer to Special Instruction, REHS0923 for information on calibration and adjustment.Liquid Level Switch
Illustration 8 g00763723
The switch provides an alarm signal if the water level in the expansion tank is too low. The switch is wired in the normally open position. A normal water level in the expansion tank holds the contacts of the switch closed. If the water level falls and the contacts break, the I:3.0/5 input of the PLC becomes inactive. An alarm is then generated.Oil Mist Detector
Illustration 9 g00763727
The system is used in order to detect the presence of an oil mist in the crankcase. An oil