Usage:
3.1: Component List
- Mounting Group 9X9621Personality Module (Blank) 9X6813Program Personality Module
- 3516 (standard) 3E01193516 (optional) 3E18663512 (standard) 3E18183508 (Standard) 3E3411
NOTE: The four standard personality modules are configured for four axle locomotives with parallel traction motor connections in motoring mode. The 3508 and 3512 modules do not include dynamic brake regulation. The standard 3516 module has dynamic brake lever schedules for 700 amp grids and the optional 3516 module has dynamic brake lever schedules for 900 amp grids.
Mounting Group
The 9X9621 Mounting Group contains Caterpillar electronic locomotive control, protection diodes, derate module, and locomotive industry terminal strips. This group comes factory pre-wired. During installation all connections are made on two terminal blocks (TB391 and TB392).
3.2.1: Locomotive Governor (9X9623)
Locomotive Governor
The main electronic governor controls engine speed, and the load on the engine by controlling the power output of the generator which drives the locomotive traction motors.
3.2.2: Altitude Derate Module (9X6801)
Altitude Derate Module
The altitude derate module provides four additional analog input signals to the main electronic governor.
These inputs are used by the main electronic governor to perform a variety of functions. The input signals to the altitude derate module range from 0 to 50 volts DC full scale, except for the pressure sensor which is contained within the module. The input signal for the pressure sensor is 0 to 5 volts DC full scale.
There are two types of derate modules. One is the standard derate module (8C5671). The other is the altitude derate module (9X6801). The production 3500 Series Locomotives use the 9X9621 mounting group. The altitude derate module is installed on the mounting group and comes factory pre-wired.
The five channels used on the Altitude Derate Module are:
- Channel 1 High Motor Current SignalChannel 2 Low High Motor Current SignalChannel 3 Dynamic Brake Lever SignalChannel 4 Pressure (Barometric) Sensor SignalChannel 5 Coolant Temperature Signal
3.2.3: Standard Derate Module (8C5671)
Standard Derate Module
There are some SER engines with the standard derate module. The standard derate module will accept five analog signals. The input signals to the derate module range from 0 to 50 volts DC. The derate module produces one digital signal to the main electronic governor. The standard derate module does not have any altitude sensing capability and must be wired properly to disable the altitude derate strategy.
3.2.4: Protection Diode Block (7C2668)
Protection Diode Block
The diode block module provides protection against electrical transients to the main electronic governor power supply inputs.
3.2.5: Diagnostic Decal (9X9390)
Diagnostic Decal
The main electronic governor has eight status LED's on its front face. The diagnostic decal is used to convert LED status to status/diagnostic information.
3.3: Complimentary Diagnostic Decal (3E0280)
This decal will explain in more detail the Engine/Locomotive diagnostics displayed by the main electronic governor system.
3.4: Personality Module
Personality Module
This module contains the required software to control engine speed and engine load. There are several programmed personality modules available depending on the engine type and applications. Refer to 3500 Locomotive Engines, Personality Module Settings, SENR5187, for the detail settings.
This module also contains the calibration mode switch (used to calibrate the rack position sensor) and on some applications adjustments for low idle settings.
3.5: Engine Speed Sensor
Engine Speed Sensor
The engine speed sensor provides a digital signal. The frequency of this signal represents engine speed to the main electronic governor. The location of the sensor depends on the engine type. It is normally mounted on the flywheel housing adjacent to the ring gear teeth. The speed sensor magnetically detects the gear teeth as they pass by and generates a corresponding AC voltage. Electronics inside the sensor convert the AC voltage into a digital voltage signal.
3.6: Rack Position Sensor
Rack Position Sensor
The rack position sensor measures fuel rack position. The sensor sends a digitally coded signal to the main electronic governor. The sensor assembly includes a linear potentiometer and an active electronic module that digitally encodes the potentiometer signal.
3.7: Temperature Sensor
Temperature Sensor
The temperature sensor is a thermistor type and measures the coolant temperature.
3.8: Temperature Interface Module
Temperature Interface Module
The temperature sensor measures the coolant temperature and through the temperature interface module produces a 0 to 50 volt analog signal to the derate module. The derate module will then provide this signal to the main electronic governor.
3.9: Current Transformers (CT)
The current transformers are located in the Kato generator. Refer to the respective parts manual for replacement information.
3.10: Potential Transformers (PT)
The potential transformers are located in the Kato generator. Refer to the respective parts manual for replacement information.
3.11: Scaling Network
Scaling Network
Scaling Network Block Diagram
The generator current and voltage sense feedback signals are generated by factory installed Potential and Current Transformers mounted in the generator housing. Potential and Current Transformers are used to sense power at the AC section of the generator. These signals are then rectified and scaled by the scaling network to generate voltage and current feedback signals to the main electronic control governor.
3.12: Transductors
Transductor
The individual motor armature currents (also if Dynamic Brakes are fitted, the grid cooling fan current) are each measured by a transductor. These transductors must be excited by one phase of the three phase auxiliary alternator which is part of the standard 3500 Locomotive Engine package. The transductors have a ratio of 1000:1 and generate a 0 to 1.5 amp AC current signal over the full range of the motor currents (1500 amps).
3.13: Four Axle Wheelslip Group
Four Axle Wheelslip Group With dynamic brake upgrade group installed.
The four axle wheelslip group comes factory pre-wired. This group contains a wheelslip module and four transductor input modules. The wheelslip groups are different depending on the locomotive system. They are:
- 4 Axle Wheelslip - 750 amp Dynamic Brake Grid Alarm (4P2714)4 Axle Wheelslip - 950 amp Dynamic Brake Grid Alarm (4P2715)
3.14: Transductors Input Module
Transductor Input Module
The transductor input module converts 0 to 1.5 amp AC current signal from the transductors to a 0 to 15 volt DC signal which corresponds to 0 to 1500 amp motor current. This input module consists of a step down current transformer, full wave rectifier bridge and a current sensing resistor. The reference for the output signal of this input module is therefore isolated from both the transductor excitation power and also the battery power.
3.15: Wheelslip Module
Wheelslip Module
(1) 750 amp Dynamic Brake Grid Alarm.
The wheelslip module compares the DC signals from each of the input modules and generates two output signals. One signal is proportional to the level of the highest motor current. The second signal is proportional to the level of the lowest motor current. The wheelslip module also amplifies these two signals to a full scale of 50 volts DC. The reference for these output signals from the wheelslip module is battery negative (-). The wheelslip module generates a floating reference for the input signals from the input modules. The wheelslip module also provides the grid fan failure alarm feature.
Refer to diagram 23 in "4.12: Installation Diagrams" for a block diagram of the wheelslip motor current module.
These two motor current signals are inputs to the main electronic governor. It uses them to regulate:
- * High Motor Current
- * High Grid Current (if Dynamic Brakes are fitted)
- * Differential Wheelslip
- * High Grid Current (if Dynamic Brakes are fitted)
Different wheelslip modules are used depending on the locomotive system configuration. They are:
- * Wheelslip Module - 750 amp Dynamic Brake Grid Alarm (7E5158)
- * Wheelslip Module - 950 amp Dynamic Brake Grid Alarm (4P2716)
3.16: Sanding Relay Assembly
Sanding Relay Assembly
3.17: Actuator
The Electronic Locomotive Control Box is designed to drive a Woodward Rack Actuator. Woodward makes a wide range of electro-hydraulic actuators that share a common electrical interface and can all be driven by the Electronic Locomotive Control Box. The actuator used depends on the type of engine and the application. The EG-10P actuator is usually used on the 3500 series engines. The actuator is mechanically connected to the engine's rack linkage which positions the rack as a function of the drive current from the Electronic Locomotive Control Box. The relationship between rack position and drive current is very close to linear.
3.17.1: EG-10P Actuator
Actuator
(1) EG-10P Actuator
The EG-10P Actuator is an engine driven device that hydraulically changes an electrical input to a mechanical output (terminal shaft rotation) that controls the engine fuel rack.
This actuator is used with the Electronic Locomotive Control Box. The Electronic Locomotive Control Box sends a voltage input signal to the solenoid coils of the actuator. The position of the actuator terminal (output) shaft is directly proportional to this input signal to the actuator. When the voltage signal to the actuator is stopped, the terminal shaft of the actuator will move to a position to shut the fuel off to the engine.
The direction of rotation for the correct oil flow is determined at the factory by placement of plugs in specific oil passages in the actuator base and case. There is a relief valve in the actuator to maintain operating oil pressure at a minimum of 1723 kPa (250 psi). Some older units operate at 2750 kPa (400 psi).
NOTE: The only adjustment that can be made to the EG-10P Actuator is the external needle valve. Refer to subject Needle Valve.
To better understand the complete operation of the actuator, a separate explanation of each system follows. These systems are: Oil Pump, Mechanical, Electrical, Hydraulic and Feedback (Mechanical & Hydraulic Buffer).
Schematic Of EG-10P Actuator
Oil Pump System
Engine lubrication oil is supplied (from the engine sump) through inside passages to the suction sides of the three gear actuator oil pump. The pump gears push the oil to the pressure side of the pump to fill the system and increase the hydraulic pressure. When the pressure becomes great enough to overcome the force of the relief valve spring, the relief valve plunger is pushed down to uncover the bypass opening. This bypass oil now goes back to the inlet side of the pump.
Basic Mechanical System
The power piston is connected to the actuator terminal (output) shaft. The engine fuel rack linkage is also connected to the terminal shaft. When there is an increase or decrease in engine load, the movement of the power piston will turn the terminal shaft. The linkage will now move the fuel racks to the new fuel setting to maintain the correct engine speed at the new load condition.
Basic Electrical System
An engine speed sensor is installed in the flywheel housing of the engine to make an AC voltage signal. The frequency of this AC signal is controlled by the speed of the gear teeth that pass through the magnetic field of the pickup. This engine speed frequency signal is sent to the Electric Locomotive Control Box. The Electric Locomotive Control Box makes a comparison between this input signal for actual engine speed and the desired engine speed that the control box has been set to maintain. If the actual engine speed and the speed setting are not the same, the Control Box will send a corrected DC voltage signal to the solenoid coils of the actuator. The actuator will now adjust to a new fuel setting to make the engine speed the same as the speed setting.
The pilot valve plunger is connected to a permanent magnet that is spring-suspended in the field of a two-coil solenoid. The output signal from the Control Box is applied to the solenoid coils to make a magnetic force which is proportional to the current in the coils. This force always tries to move the magnet and pilot valve plunger in the down (increase fuel) direction. The centering spring (at top of plunger) force always tries to move the magnet and pilot valve plunger in the up (decrease fuel) direction.
When the unit runs on-speed at steady-state conditions, these two forces are equal but in opposite directions. The pilot valve plunger at this time will be "centered" (the control land covers the control port).
If there is a decrease in the engine speed setting at the Control Box, or an increase in engine speed (because of a decrease in the engine load), the input voltage to the actuator solenoid coils will be decreased. The magnetic force of the solenoid coils also will now be decreased. Since the force of the centering spring is now greater than the force of the coils, the pilot valve plunger will move above the "centered" position. This allows oil under the power piston to drain to sump, and the down movement of the power piston will cause rotation of terminal shaft in the decrease fuel direction.
If there is an increase in the engine speed setting at the Control Box, or a decrease in engine speed (because of an increase in engine load), the input voltage to the actuator solenoid coils will be increased. The magnetic force of the solenoid coils also will now be increased. Now the force of the coils will be greater than the force of the centering spring, and the pilot valve plunger will move down to allow pressure oil under the power piston.
Since the surface area (that oil pressure works against) of the power piston is larger at the bottom than at the top, the piston will move up. The rotation of the terminal shaft will now be in the increase fuel direction.
Basic Hydraulic System
The power piston is the part of the actuator that does all of th work. Under normal conditions, the oil pressures at both the top and bottom of the piston are balanced, and the piston remains stationary at the "centered" position. The pilot valve plunger controls the flow of oil to and from the power piston. The control land at the bottom of the pilot valve plunger is just large enough to completely cover the control port in th pilot valve bushing when the plunger is exactly "centered".
If the signal from the Electronic Locomotive Control Box makes the pilot valve plunger move up, the oil under the power piston can drain past the control land to sump. The higher oil pressure at the top of the piston will now move the piston down until the control land of the plunger will again close the control port. This piston movement will also move the terminal shaft (in the decrease fuel direction), since they are connected together.
If the signal from the Electronic Locomotive Control Box makes the pilot valve plunger (and control land) move down, pump oil pressure can now pass through the control port to the bottom of the piston. Even though the pump oil pressure in the circuit above the piston is the same as the circuit below the piston, the piston will move up. This is due to a larger surface area available to the oil pressure at the bottom of the piston than the surface area at the top of the piston. The movement of the piston will now turn the terminal shaft in the increase fuel direction.
Feedback Systems
A high degree of stability is necessary to maintain a constant output from the generator set. The stability of a system controlled by the Electronic Locomotive Control Box is increased with the use of a temporary actuator feedback signal that biases (makes a correction to) the Control Box command signal to the pilot valve plunger. Since the Control Box makes an adjustment rapidly to a change in engine load, the actuator can make the engine go into a "hunt" condition (temporary increase and decrease in engine speed) if the corrections are too sensitive. The purpose of the feedback system is to prevent over-correction to the load change.
The EG-10P Actuator is different because two feedback systems are used, one mechanical and one hydraulic. Under normal conditions, the mechanical system will correctly control the actuator. However, during cold engine start-up conditions, the addition of the hydraulic buffer system eliminates erratic (variable) speed problems caused by the cold engine oil. The result of the two systems is constant speed control at all times. The explanation for the operation of each feedback system is as follows:
Mechanical Feedback System
The temporary feedback signal is accomplished in this system by the addition of linkage and a restoring spring arrangement that applies a secondary force to the centering spring.
Decreased Engine Load
With this condition, the voltage signal to the solenoid coils is decreased and the centering spring force will raise the pilot valve plunger to release oil under the power piston to sump. The power piston will now move down to turn terminal shaft in the decrease fuel direction. The mechanical linkage of the feedback lever is also connected to the terminal shaft and will move down. The restoring lever will also move down to put the restoring spring in compression. The restoring spring force is opposite the upward force of the centering spring. The resultant force (from the restoring lever and restoring spring) will now help the solenoid move the pilot valve plunger back down to the "centered" position before it would have been moved down by just the voltage signal change to the solenoid itself. Therefore, the actuator acts to position the terminal shaft in the new decreased fuel position without allowing an underspeed condition.
Increased Engine Load
This condition will increase the voltage signal to the solenoid coils, and the pilot valve plunger will move down because the magnetic force is greater than the centering spring force. The control land will now let pressure oil to the bottom of the power piston, and the power piston will move up. The terminal shaft will turn in the increase fuel direction and, at the same time, move the feedback lever and the restoring lever up. Now there is less compression on the restoring spring.
The resultant centering spring force (upward) is now stronger than the magnetic force of the solenoid coils, and the pilot valve plunger will move up to the "centered" position before it would have been moved up by just the voltage signal change to the solenoid itself. Therefore, the actuator has moved the terminal shaft in the increased fuel position without allowing an overspeed condition.
Hydraulic Buffer Feedback System
The temporary feedback signal in this system uses a pressure differential that is applied across the compensation land of the pilot valve plunger. This pressure differential is accomplished by the buffer system.
Decreased Engine Load
With the pilot valve "centered", no oil flows to or from the power piston. If there is a decrease in load (causing an increase in engine speed), the solenoid coils will get a voltage signal to lift the pilot valve plunger. The oil under the power piston will now be released to go to sump. Pump pressure oil on the right side of the buffer piston will now force the buffer piston to the left. This displacement of oil in the power cylinder oil pressure circuit will move the power piston down and cause rotation of the terminal shaft in the decrease fuel direction.
The movement of the buffer piston to the left also decreases the compression of the buffer spring on the right side, and increases the compression of the buffer spring on the left side. The increase of the left buffer spring force (caused by resistance to this movement) results in a small decrease in oil pressure on the left side of the buffer piston and on the bottom surface of the pilot valve plunger compensation land. This pressure difference on the two sides of the compensation land makes a force (greater at the top) to push the pilot valve plunger back down to the "centered" position.
When the terminal shaft has turned far enough to satisfy the new fuel requirement, the force of the pressure difference on the compensation land will have again "centered" the pilot valve plunger (even though the engine speed is not yet completely back to normal). The movement of the power piston, and the terminal shaft, is now stopped.
The continued decrease of engine speed to its steady-state setting results in a continued increase in downward force to the pilot valve plunger as the Electronic Control signal (to the solenoid coils) increases to its on-speed value. At the same time, the pressure difference on each side of the buffer piston (and at top and bottom of the compensation land) is being released by the flow of oil through the needle valve orifice. This controlled discharge allows the buffer piston to return slowly to its normal, "centered" position. The increase in the solenoid voltage signal to its on-speed value, and the controlled reduction of the pressure difference on the two sides of the compensation land occur exactly at the same rate (while the pilot valve plunger remains "centered") until the engine is again at the on-speed condition at the decreased load.
Increased Engine Load
When the engine load is increased, engine speed will decrease. The Electronic Locomotive Control Box will now send a stronger signal (more voltage) to the solenoid coils, and the pilot valve plunger will move down. The control land has now opened the control port to allow pump pressure oil to the bottom of the power piston. Even though the pressure on each side of the power piston is approximately the same at this time, the pressure against the larger surface area at the bottom of the piston makes a larger force and the power piston will move up. This upward piston movement will cause terminal shaft rotation in the increase fuel direction, and the engine speed will begin to increase.
When the power piston moves up, the displacement of the oil above the power piston will move the buffer piston to the right. This movement will cause a pressure increase on the bottom surface of the compensation land. The pilot valve plunger will now move up to close the control port of the pilot valve bushing before engine speed returns to normal. Any movement of the power piston, and the terminal shaft, is now stopped.
As the engine starts its return to normal speed, the controlled discharge of the oil pressure difference through the needle valve orifice is at the same rate that the voltage signal is decreased to the solenoid coils. The engine now returns to its steady-state condition, with the terminal shaft already set at the new fuel position that is required for the increase in engine load.
Needle Valve
The needle valve orifice is adjustable to permit a variable time rate that a pressure differential acts on the compensation land of the pilot valve plunger. This permits limited control of the EG-10P actuator to be calibrated (set) to the response characteristics of the engine. Normally the settings can be made in the range of 1/2 to 1 1/2 turns open to get the desired characteristics.
3.18: Junction Box
Engine Junction Box
(1) DC-DC converter. (2) Electronic speed switch. (3) Diode blocks. (4) Slave relays. (5) Terminal boards.
This junction box contains the engine protection and shutdown logic.