2819638 ENGINE AR-COMPLETE Caterpillar parts
C7
Rating:
Alternative (cross code) number:
CA2819638
281-9638
2819638
CA2819638
281-9638
2819638
TRUCK ENGINE,
Compatible equipment models: 2819638:
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Sensors (Construction, Operating Principle and Characteristics)
Thermo Unit
Construction
Construction of Thermo UnitOperating PrincipleA thermistor has characteristics of a high temperature coefficient of resistance.In short, its resistance changes very widely with temperature. When the temperature is low, its resistance increases, making it harder for meter current to flow. When the temperature is high, on the other hand, its resistance decreases, allowing large meter current to flowCharacteristics Fuel Tank Unit
Construction
Construction of Fuel Tank UnitOperating PrincipleThe position of the float changes with the residual quantity of fuel and causes the contact mounted at the bottom of the arm to move on the resistance wire, changing the resistance value to the one that corresponds to the residual quantity.Characteristics
Characteristics Value (*Reference values shown)Thermo Switch
Construction
Construction of Thermo SwitchOperating Principle (Circuit Configuration)Temperature rise causes contact to operate. Operating Temperature Pressure Switch
Construction
Construction of Pressure SwitchOperating Principle (Circuit Configuration)Oil pressure causes switch contact to change. Operating Pressure Operation of Monitoring System
Coolant Temperature Gauge, Hydraulic Oil Temperature Gauge and Fuel Gauge
Equivalent Circuit of Movement Operating PrincipleIf the resistance of the sensor changes, the currents (ia and ib) flowing through the coils change. As a result, the direction of the combined magnetic force (F) of the magnetomotive force generated in the respective coils moves. Following it, the moving magnet turns, simultaneously causing the pointer to deflect to present an indication.HOUR MeterBasic Contruction of Movement Operating PrincipleThe oscillation drive circuit section is designed for rotating the motor at a constant speed. The circuit section uses an IC. The IC, combined with a crystal oscillator, has functions for performing a series of oscillation, frequency division and amplification. The oscillation frequency of 4.2 MHz from the crystal is demultiplied in 22 stages, 1/2 a stage, for ultimate countdown to 1 Hz, and the signal amplified to a level high enough to drive the motor. The rotation transmission section consists of a pulse motor and reduction mechanism. The pulse motor has 10 magnetized poles. The 10 motor poles and the input signal of 1 PPS cause the motor to rotate at 6 rpm (360 rph). The reduction mechanism is a combination of four stages of gears to provide a reduction ratio of 1/360, thereby causing the total wheel to turn through a rotating in an hour.The total wheel displays five digits, the lowest digit indicating 1/10 hours.Operation of Alarm Circuit
Power Supply CircuitWhen the starting switch is placed in the ON position and 24V supplied to terminal (10) of the connector, transistor TR2 is caused to be ON. And the constant voltage from zener diode Z2 applied to the base of transistor TR3 and 15V constant voltage available from the emitter of TR3.Capacitor C31 is provided for smoothing the pulsating components included in the 15V constant voltage. When foreign surges are applied, transistor TR1 is driven to the ON state to force transistors TR2 and TR3 to the OFF stage for protection of the whole circuit. CHARGE Lamp Circuit When the engine stops or when there is a problem in the charge system, the relay stays
Thermo Unit
Construction
Construction of Thermo UnitOperating PrincipleA thermistor has characteristics of a high temperature coefficient of resistance.In short, its resistance changes very widely with temperature. When the temperature is low, its resistance increases, making it harder for meter current to flow. When the temperature is high, on the other hand, its resistance decreases, allowing large meter current to flowCharacteristics Fuel Tank Unit
Construction
Construction of Fuel Tank UnitOperating PrincipleThe position of the float changes with the residual quantity of fuel and causes the contact mounted at the bottom of the arm to move on the resistance wire, changing the resistance value to the one that corresponds to the residual quantity.Characteristics
Characteristics Value (*Reference values shown)Thermo Switch
Construction
Construction of Thermo SwitchOperating Principle (Circuit Configuration)Temperature rise causes contact to operate. Operating Temperature Pressure Switch
Construction
Construction of Pressure SwitchOperating Principle (Circuit Configuration)Oil pressure causes switch contact to change. Operating Pressure Operation of Monitoring System
Coolant Temperature Gauge, Hydraulic Oil Temperature Gauge and Fuel Gauge
Equivalent Circuit of Movement Operating PrincipleIf the resistance of the sensor changes, the currents (ia and ib) flowing through the coils change. As a result, the direction of the combined magnetic force (F) of the magnetomotive force generated in the respective coils moves. Following it, the moving magnet turns, simultaneously causing the pointer to deflect to present an indication.HOUR MeterBasic Contruction of Movement Operating PrincipleThe oscillation drive circuit section is designed for rotating the motor at a constant speed. The circuit section uses an IC. The IC, combined with a crystal oscillator, has functions for performing a series of oscillation, frequency division and amplification. The oscillation frequency of 4.2 MHz from the crystal is demultiplied in 22 stages, 1/2 a stage, for ultimate countdown to 1 Hz, and the signal amplified to a level high enough to drive the motor. The rotation transmission section consists of a pulse motor and reduction mechanism. The pulse motor has 10 magnetized poles. The 10 motor poles and the input signal of 1 PPS cause the motor to rotate at 6 rpm (360 rph). The reduction mechanism is a combination of four stages of gears to provide a reduction ratio of 1/360, thereby causing the total wheel to turn through a rotating in an hour.The total wheel displays five digits, the lowest digit indicating 1/10 hours.Operation of Alarm Circuit
Power Supply CircuitWhen the starting switch is placed in the ON position and 24V supplied to terminal (10) of the connector, transistor TR2 is caused to be ON. And the constant voltage from zener diode Z2 applied to the base of transistor TR3 and 15V constant voltage available from the emitter of TR3.Capacitor C31 is provided for smoothing the pulsating components included in the 15V constant voltage. When foreign surges are applied, transistor TR1 is driven to the ON state to force transistors TR2 and TR3 to the OFF stage for protection of the whole circuit. CHARGE Lamp Circuit When the engine stops or when there is a problem in the charge system, the relay stays