Usage:
The E30 Electric Governor Control System consists of the following components:
- * KG30 Governor Control Unit
- * Actuator
- * Magnetic Pickup
- * Actuator
KG30 Governor Control Unit
The E30 Electric Governor Control System allows precision engine speed control. The KG30 Governor Control Unit measures engine speed constantly and makes necessary corrections to the engine fuel setting through the actuator which is connected to the fuel system.
The engine speed is sensed by a magnetic pickup. The magnetic pickup generates an AC voltage that is sent to the KG30 Governor Control Unit. The KG30 Governor Control Unit sends a DC voltage signal to the actuator.
Actuator (with base)
(1) Position indicator plate. (2) Connector (from the KG30 Governor Control Unit). (3) Actuator output shaft. (4) Position indicator.
Actuator (without base)
(1) Position indicator plate. (2) Connector (from the KG30 Governor Control Unit). (3) Actuator output shaft. (4) Position indicator.
The actuator changes the electrical input from the KG30 Governor Control Unit to a mechanical output that is connected to the fuel system by a linkage. For example, if the engine speed is greater than the speed setting, the KG30 Governor Control Unit will decrease its output and the actuator will move the linkage to decrease fuel to the engine.
The speed of the engine is adjusted between IDLE, and RATED, with the Remote Speed Setpoint potentiometer.
Basic System Schematic
(5) Actuator. (6) Engine. (7) Feedback line. (8) Magnetic pickup. (9) KG30 Governor Control Unit. (10) Remote Speed Setpoint potentiometer (11) Fuse.
KG30 Governor Control Unit
KG30 Governor Control Unit
(1) Diode. (2) Maximum Fuel 5V potentiometer. (3) Stop 1.5V potentiometer. (4) Minimum Speed potentiometer. (5) Maximum Speed potentiometer. (6) Gain potentiometer. (7) Stability potentiometer. (8) Derivative potentiometer. (9) Gas Gain potentiometer. (10) Gas Diesel switch. (11) Start Fuel Limit potentiometer. (12) Start Fuel Limit slide switch. (13) Green, Light Emitting Diode (LED). (14) OV (-). (15) TP6 (+). (16) Droop potentiometer. (17) Droop Isochronous switch. (18) Speed Variance potentiometer. (19) Fast Response potentiometer. (20) Damping potentiometer.
KG30 Governor Control Unit Earlier, (green control board)
KG30 Governor Control Unit Later, (white control board)
The KG30 Governor Control Unit provides precision engine speed control. The KG30 Governor Control Unit measures engine speed constantly, and makes necessary corrections to the engine fuel setting through the actuator connected to the fuel system.
The engine speed is sensed by a magnetic pickup. As the teeth of the flywheel ring gear cut through the magnetic lines of force around the magnetic pickup, an AC voltage is generated. The frequency of the voltage is directly proportional to the engine speed. An electric circuit inside the KG30 Governor Control Unit processes the AC voltage. In response, the electric circuit sends a signal from the KG30 Governor Control Unit to the actuator, maintaining the set speed.
The actuator is connected to the fuel system by linkage. The actuator changes the electrical input from the KG30 Governor Control Unit to mechanical output, changing the engine fuel setting. For example, if the engine speed is greater than the speed setting, the KG30 Governor Control Unit decreases fuel to the engine.
The RATED, and LOW IDLE engine speeds are set with internal speed setting potentiometers. The engine speed is adjusted with a remote, 10 turn potentiometer, or as a function of voltage, current, or air pressure with an optional speed setpoint unit.
The Gain, Stability, and Derivative potentiometers control the speed stability and the response time of the engine to a change in load. Gain, affects the amount of speed deviation and recovery time. Stability, affects the rate of recovery, overshoot, and response time for the Gain setting used. Derivative, affects the rate of speed deviation and response time to some degree, but is mainly for additional fine tuning of engine stability.
The Speed Droop potentiometer controls the amount of speed droop. The Speed Droop potentiometer can be set between 0 and 10 percent. The Speed Droop potentiometer may be necessary for some twin engine systems driving a common gearbox, or when used with an engine equipped with a hydra-mechanical governor. The Speed Droop potentiometer is sometimes used to increase engine stability.
The Start Fuel Limit potentiometer is used to control the amount of fuel to the engine during STARTUP. The Start Fuel Limit potentiometer can be adjusted to make the engine START easier, decrease STARTUP smoke, and limit STARTUP overshoot. The Fuel Limiting function is turned OFF automatically when the speed control takes over.
The Speed Failsafe circuit drives the actuator to SHUTOFF if the magnetic pickup signal becomes less than 150 Hz. Magnetic pickup failure or slow engine cranking causes the actuator to move to the FUEL OFF position. The engine will NOT start if the magnetic pickup signal has a failure.
Actuator (StG30)
Actuator
(1) Actuator output shaft. (2) Feedback probe. (3) Feedback cam. (4) DC disc armature motor. (5) Gearbox.
Actuator torque is generated by a DC disc armature motor (4) and transmitted to the actuator output shaft (1) by way of a gearbox (5).
A feedback cam (3) is mounted on the actuator output shaft (1) which is scanned without contact by a feedback probe (2). The precise position of the actuator output shaft (1) is transmitted to the KG30 Governor Control Unit.
If the actuator is driven against a fuel rack stop, the current limitation takes effect after approximately 20 seconds. The fuel rack stop reduces the current to the actuator to a value that cannot harm the motor.
The actuator provides the following advantages:
- * High regulating power working in both directions.
- * Extremely low current consumption during steady state, and relatively low current consumption on change of load.
- * Indifference to slow voltage changes in the supply.
- * Extremely low current consumption during steady state, and relatively low current consumption on change of load.
Basic Mechanical System
The engine fuel rack linkage is connected to the actuator terminal shaft. When there is an increase or decrease in engine load, the movement of the actuator motor turns the terminal shaft. The linkage moves the fuel racks to the new fuel setting to maintain the correct engine speed at the new load condition.
Basic Electrical System
A magnetic pickup is installed in the flywheel housing to generate an AC voltage signal. The frequency of this AC signal is controlled by the speed of the gear teeth that cut through the magnetic field of the pickup. This engine speed frequency signal is sent to the KG30 Governor Control Unit.
The KG30 Governor Control Unit has a speed sensor that compares the input signal for actual engine speed, and the desired engine speed the KG30 Governor Control Unit has been set to maintain. If the actual engine speed and the speed setting are NOT the same, the KG30 Governor Control Unit sends a corrective signal to the motor of the actuator. The actuator adjusts to a new fuel setting to make the engine speed the same as the speed setting.
Feedback System
A high degree of stability is necessary to maintain a constant output from the engine. The stability of a system controlled by the KG30 Governor Control Unit is increased with the use of the actuator feedback signal that biases (makes a correction to) the KG30 Governor Control Unit command signal to the actuator.
The KG30 Governor Control Unit can make a rapid adjustment to a change in the engine load, and 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 feedback system allows a means of providing equal fuel load sharing between two engines driving a common gearbox, by using an optional accessory unit.
Magnetic Pickup
Schematic Of The Magnetic Pickup
(1) Magnetic lines of force. (2) Wire coils. (3) Gap. (4) Magnet pole piece. (5) Flywheel ring gear.
The magnetic pickup is a single pole, permanent magnet generator made of wire coils (2) around a permanent magnet pole piece (4). As the teeth of the flywheel ring gear (5) cut through the magnetic lines of force (1) around the magnetic pickup, an AC voltage is generated. The frequency of the voltage is directly proportional to engine speed.
The engine speed frequency signal (AC) is sent to the KG30 Governor Control Unit, and a conversion is made to DC voltage. The KG30 Governor Control Unit compares the actual speed signal to the setpoint speed signal, and corrects any speed error with a signal to the actuator.