SECTION 2SYSTEM —CONTENTS— Group 1 Control System Outline .....................................................T2-1-1 Engine Control .........................................T2-1-2 Pump Control .........................................T2-1-23 Valve Control..........................................T2-1-32 Other Controls........................................T2-1-46 Group 2 Hydraulic System Outline .....................................................T2-2-1 Pilot Circuit...............................................T2-2-2 Main Circuit ............................................T2-2-12 Group 3 Electrical System Outline .....................................................T2-3-1 Main Circuit ..............................................T2-3-2 Electric Power Circuit ...............................T2-3-3 Indicator Light Check Circuit.....................T2-3-4 Accessory Circuit .....................................T2-3-5 Preheat Circuit .........................................T2-3-6 Starting Circuit .........................................T2-3-8 Charging Circuit .....................................T2-3-10 Serge Voltage Prevention Circuit ............T2-3-14 Engine Stop Circuit.................................T2-3-16 178T-2-1 (Blank) 178T-2-2 SYSTEM / Control System OUTLINE The main controller (MC) is used to control machine operations. Electronic signals from the engine control dial, various sensors and switches are sent to the MC. After processing the received signals in the logic circuit, the MC sends out control signals to the EC motor, solenoid valve units, torque control solenoid valve, and other control circuits to regulate the engine, pumps, motors and valves. Input Signals • EC Sensor • Engine Control Dial • Pump 1 Control Pressure Sensor • Pump 2 Control Pressure Sensor • Pump 1 Delivery Pressure Sensor • Pump 2 Delivery Pressure Sensor • Pump 3 Delivery Pressure Sensor (Oprtional) • N sensor Output Signals ҳ ҳ ҳ ҳ ҳ ҳ Engine Control (EC Motor) Engine Control Dial HP Mode Control E mode Control Auto-Idle Control Auto-Acceleration Control Auto-Warming Up Control Idle Speed-Up Control Engine Speed Automatic Increase Control Travel(Oniy ZAXIS270) ∗ Attachment Operation Speed Increase Control ∗ Attachment Operation Speed Limit Control Engine Learning Control ҳ ҳ • Pressure Switch (Travel) ҳ • Pressure Switch (Front Attachment) ҳ • Pressure Switch (Swing) ҳ • Pressure Switch (Boom Raise) ҳ • Pressure Switch (Arm Roll-In) ҳ • Pressure Switch (Auxiliary) ҳ • Pressure Switch (Arm Roll-Out) (Optional) ҳ • Hydraulic Oil Temperature Sensor ҳ • Auto-Idle/Acceleration Selector ҳ • Power Digging Switch ҳ • Power Mode Switch (HP/E/P) ҳ • Travel Mode Switch (Fast/Slow) ҳ • Work Mode Switch (Digging/Attachment) ҳ • Learning Switch ҳ • Key Switch ҳ • Boom Angle Sensor (Only ZAXIS225US) • Auxiliary Mode Switch (Optional) ҳ MC at Pump Control (Torque Control Solenoid Valve) Speed Sensing Control Slow Speed Torque Increase Control ∗ Pump 1 Flow Rate Limit Control ∗ Pump 2 Flow Rate Limit Control ∗ Pump 3 Torque Decrease Control Valve Control (Solenoid Valve Unit) Power Digging Control Arm Flow Rate Control Arm Regenerative Control Travel Motor Swash Angle Control Auto-Power Lift Control ∗ Auxiliary Flow Rate Control Other Controls Boom Electronic Cushion ZAXIS225US) Work Mode Control ∗ Travel Alarm Control ∗ NOTE: Only on the machines equipped with the corresponding optional parts. T2-1-1 Control (Only with the Engine Control System Layout Learning Switch Pressure Sensor Travel Front Attachment Swing Boom Raise Arm Roll-In Key Switch Pump 2 Delivery Pressure Sensor Pump 1 Delivery Pressure Sensor Auxiliary (Optional) Engine Control Dial EC Sensor Auto-Idle / Acceleration Selector Auto-Idle EC Motor Auto-Acceleration Power Mode Switch HP Mode E Mode P Mode Work Mode Switch Digging Mode Pump 2 Control Pressure Sensor Auxiliary Mode Hydraulic Oil Temperature Switch Sensor (Optional) Attachment Mode T2-1-2 Pump 1 Control Pressure Sensor T178-02-01-027 .SYSTEM / Control System ENGINE CONTROL The engine control system is grouped as follows: • • • • • • • Idle Speed-Up Control • Engine Speed Automatic Increase Control at Travel (Only ZAXIS270) ∗ • Attachment Operation Speed Increase Control ∗ • Attachment Operation Speed Limit Control • Engine Learning Control Engine Control Dial Control HP Mode Control E Mode Control Auto-Idle Control Auto-Acceleration Control Auto-Warming Up Control ∗ NOTE: Only on the machines corresponding optional parts. SYSTEM / Control System (Blank) T2-1-3 . ȀȀ Engine Speed ȀȀ Engine speed is reduced by 100 min-1 when the control levers are in neutral.SYSTEM / Control System Engine Control Dial Control Function: Controls the engine speed in response to the rotation angle of the engine control dial -1 and reduces the engine speed by 100 min to reduce fuel consumption and noise level when all control levers are in neutral. Control Range ȀȀȀ NOTE: Even if the control dial is rotated to the full speed position. 1 second after all control levers are in neutral (the travel and front attachment sensors are OFF).) Approx. Therefore. the engine speed remains unchanged. when the engine speed set by the engine control dial is already slower than the -1 maximum speed by 100 min . (Refer to the HP mode control. the MC drives the EC motor so that the engine speed is -1 reduced from the maximum speed by 100 min . T2-1-4 Minimum Speed Maximum Speed Engine Control Dial Position . This engine speed reduction control is activated regardless of whether the auto-idle and/or auto-acceleration control is activated or not. Operation: The MC drives the governor lever in response to the rotation angle of the engine control dial to regulate the engine speed. NOTE: The engine speed is reduced from the -1 maximum speed by 100 min . the governor lever doesn’t come in contact with the full speed stopper. ANIMATION SYSTEM / Control System Pressure Sensor Travel Front Attachment Engine Control Dial EC Motor T178-02-01-004 T2-1-5 . Engine Speed Operation: The MC drives the EC motor to slightly increase the engine speed set by the engine control dial when all the following conditions exist with the power mode switch is in the HP position.SYSTEM / Control System HP Mode Control Function: Slightly increases digging power such as arm roll-in operation while excavating deeply. Accordingly. Maximum speed increases by 200 min-1 except ZAXIS230 and 270 (by 100 min−1 ). 1650 min-1 1500 min-1 -1 • Engine Control Dial: Set at 1500 min or faster. the governor lever doesn’t come in contact with the stopper in the normal mode. T2-1-6 Minimum Speed Maximum Speed Engine Control Dial Position . • Boom Raise and/or Arm Roll-In Control: In Operation • Average Delivery Pressure of Pumps 1 and 2: High NOTE: The engine governor stopper position is adjusted in the HP mode. ANIMATION SYSTEM / Control System Pressure Sensor Boom Raise Arm Roll-In Pump 2 Delivery Pressure Sensor Pump 1 Delivery Pressure Sensor Engine Control Dial EC Motor Power Mode Switch HP Mode T178-02-01-005 T2-1-7 . Minimum Speed Maximum Speed Engine Control Dial Position Engine Control Dial EC Motor Power Mode Switch E Mode T178-02-01-006 T2-1-8 . Engine Speed Engine speed is reduced at the constant specified ratio. The engine speed is reduced in proportion to the rotation angle of the engine control dial.ANIMATION SYSTEM / Control System E Mode Control Function: Reduce the engine speed by the constant specified ratio. Operation: The MC drives the EC motor to reduce the engine speed set by the engine control dial when the power mode switch is in the E mode position. SYSTEM / Control System (Blank) T2-1-9 . the MC drives the EC motor so that the engine speed is reduced to the auto-idle speed.5 seconds after all control levers are return to neutral. 3. As soon as a control lever is operated (the travel and/or front attachment pressure sensor is turned ON). Operation: Approx. Auto-Idle System Deactivation Requirements: • Control Levers: Being operated (either travel or front attachment control levers with pilot sensor ON) • Power Mode Switch: When the E mode is changed to P mode or the P mode is changed to the E mode. Minimum Speed Auto-Idle Speed Maximum Speed Engine Control Dial Position . the MC drives the EC motor so that the engine speed is increased to the original engine speed (set by the engine control dial). • Engine Control Dial: When engine speed is changed.5 seconds later.SYSTEM / Control System Auto-Idle Control Function: Reduces the engine speed when all control levers are in neutral to reduce fuel consumption and noise level. T2-1-10 Engine Speed Engine speed is reduced to the auto-idle speed 3. ANIMATION SYSTEM / Control System Pressure Sensor Travel Front Attachment Engine Control Dial Auto-Idle/ Acceleration Selector Auto-Idle EC Motor Power Mode Switch E Mode T178-02-01-007 T2-1-11 . Then. In case the engine speed is set by the engine control dial and is running at a speed slower than the maximum speed by 100 -1 min . Engine speed is reduced from the maximum speed by 400 min-1 . Then. boom raise. Engine Speed Change Engine Speed Engine speed is automatically controlled in response to the control lever operations. the engine speed will be reduced by -1 300 min . 3. and arm roll-in). the optimum engine speed is selected. Operation: When a control lever is operated with the auto-idle / acceleration selector in auto acceleration position. the pump control pressure sensors. Engine Speed Change Control Lever Stroke Full Stroke NOTE: When all control levers are returned to neutral. Lever Stroke VS. Neutral Position Time Engine Speed Max. the engine speed is further reduced to the auto-idle speed. the MC drives the EC motor so that the engine speed is set to the rotation speed calculated by the MC. the engine speed is reduced to reduce fuel consumption and noise level. the engine speed is reduced by -1 400 min from the maximum speed. When all the control levers are in neutral. swing. Engine Speed (P Mode) In response to the control lever stroke and the pump delivery pressure. Engine speed is reduced to the auto-idle speed 3.5 seconds later. the MC calculates the most proper engine operating speed corresponding to the signals from pressure sensors (travel.SYSTEM / Control System Auto-Acceleration Control Function: Automatically regulates the engine speed to meet the machine operating conditions. the engine speed is reduced by 400 -1 min from the maximum speed first. and the pump delivery pressure sensors.5 seconds later. When all control levers are returned to neutral. Auto Acceleration Control Auto-Idle Engine Speed Time T2-1-12 . ȀȀ Minimum Speed Auto-Idle Speed Maximum Speed Engine Control Dial Position Operating Time Progress VS. ANIMATION SYSTEM / Control System Pressure Sensor Travel Swing Boom Raise Arm Roll-In Pump 2 Delivery Pressure Sensor Pump 1 Delivery Pressure Sensor Engine Control Dial Auto-Idle/ Acceleration Selector AutoAcceleration EC Motor Pump 2 Control Pressure Sensor Pump 1 Control Pressure Sensor T178-02-01-008 T2-1-13 . or wait to adjust until 15 minutes after starting the engine. the MC drives the EC motor in response to signals from the key switch and the hydraulic oil temperature sensor to run the engine at the auto warm up speed for 15 minutes after starting the engine.ANIMATION SYSTEM / Control System Auto-Warming Up Control Engine Speed Function: Automatically warms up the hydraulic system (similar to the auto choke on automobiles). IMPORTANT: When adjusting the auto-idle speed deactivate the auto warming up control function using Dr. ȀȀȀȀȀ Operation: When the hydraulic oil temperature is below 0 °C (32 °F). EX. Increasing Speed Minimum Maximum Speed Speed Auto Warm Up Speed Engine Control Dial Position Key Switch Engine Control Dial EC Motor Hydraulic Oil Temperature Sensor T178-02-01-009 T2-1-14 . Engine Speed Increasing Speed Minimum Speed Maximum Speed Idle Speed-Up Speed Engine Control Dial Position Pressure Sensor Travel Front Attachment Engine Control Dial EC Motor T178-02-01-010 T2-1-15 . Operation: When the travel or front attachment function is operated while the engine is running at a speed between the minimum speed and the Idle Speed-Up Speed. the MC drives the EC motor so that the engine speed is increased to the Idle Speed-Up Speed.ANIMATION SYSTEM / Control System Idle Speed-Up Control Function: Prevents the engine from hunting when running the engine at slow speed. Operation: MC drives EC motor to increase the engine speed by 100 min−1 (rpm) when the power mode switch is turned to P or HP and the following conditions exist. so that the travel speed increases. Condition: Engine Control Dial: The speed is set to maximum. Consequently. Travel Operation: Operated Front Attachment Operation: Not operated Pressure Sensor Travel Front Attachment Engine Control Dial EC Motor T1HG-02-01-001 T2-1-16 .ANIMATION SYSTEM / Control System Engine Speed Automatic Increase Control at Travel (Only ZAXIS270) Function: Increases the engine speed at travel single operation to increase the travel speed. the pump delivery flow rate increases. SYSTEM / Control System (Blank) T2-1-17 . NOTE: When the P mode engine speed is preset to a slower speed in the Dr. EX: Resets the maximum engine speed to a faster (+) attachment (hydraulic breaker. secondary crusher. primary crusher or vibrating hammer) operating engine speed set by Dr. the maximum engine speed is increased to the speed set by Dr. the maximum engine speed won’t be increased when operating the attachment. the MC drives the EC motor so that the engine maximum speed is increased to the attachment operating speed set by Dr. EX. primary crusher. Engine Control Dial: Maximum Speed Position Power Mode Switch: HP Mode Auxiliary: In Operation Work Mode Switch: Attachment Mode Auxiliary Mode Switch (Optional): Attachment position (hydraulic breaker. Engine Speed Function: Increases the maximum engine speed to the attachment (hydraulic breaker. or vibrating hammer) reset by Dr. EX.) When all conditions exist. T2-1-18 Minimum Speed Maximum Speed Engine Control Dial Position . Operating Conditions: Dr. EX when the attachment is operated. or vibrating hammer) operating speed in the service mode. primary crusher. secondary crusher. secondary crusher. EX service mode.SYSTEM / Control System Attachment Operation Speed Increase Control (Only on the machines equipped with the auxiliary mode switch (Optional). EX when the attachment is operated. Operation: When the following conditions exist. ANIMATION SYSTEM / Control System Pressure Sensor Auxiliary(Optional) Engine Control Dial EC Motor Power Mode Switch HP Mode Work Mode Switch Auxiliary Mode Switch (Optional) Attachment Mode T2-1-19 T178-02-01-011 . or vibrating hammer) set by Dr. secondary crusher. the MC drives the EC motor so that the engine maximum speed is reduced to the attachment operating speed set by Dr. EX when the attachment mode is selected. Work Mode Switch: Attachment Mode Auxiliary Mode Switch (Optional): Attachment position (hydraulic breaker. primary crusher or vibrating hammer) operating engine speed set by Dr. EX when the attachment mode is selected. secondary crusher. Engine Speed When all conditions exist. ȀȀ ȀȀȀ Operation: When the following conditions exists. EX: Resets the maximum engine speed to a slower (−) attachment (hydraulic breaker. Minimum Speed Maximum Speed Engine Control Dial Position Operating Conditions: Dr. EX.ANIMATION SYSTEM / Control System Attachment Operation Speed Limit Control (Only on the machines equipped with the auxiliary mode switch (Optional). EX. the maximum engine speed is reduced to the speed set by Dr. EC Motor Work Mode Switch Auxiliary Mode Switch (Optional) Attachment Mode T2-1-20 T178-02-01-012 . primary crusher.) Function: Decreases the maximum engine speed to the attachment (hydraulic breaker. secondary crusher. or vibrator) operating speed in the service mode. primary crusher. • After the engine. the EC motor is driven by the signals from the MC. The MC stores these signals in its memory. The EC motor moves the governor lever from the IDLE to FULL and to STOP positions in this order. The EC sensor detects the stopper positions of the governor lever on both the FULL and STOP sides and sends each stopper position signal to the MC. • After the MC has been replaced. engine control cable. EX. Operation:When the learning switch in the rear console is turned to the engine learning position. IMPORTANT: Be sure to perform the engine learning if the following repair work is done.) After performing the engine learning. check that the engine learning has been performed correctly using Dr. (Refer to the Troubleshooting Section in T/M. Learning Switch Key Switch EC Sensor EC Motor T178-02-01-014 T2-1-21 . NOTE: The engine learning is not required when the batteries are replaced. or EC motor has been removed or replaced.SYSTEM / Control System Engine Learning Control Function: Inputs the governor lever stopper positions on both the STOP and FULL sides as the standard data to control the engine. SYSTEM / Control System (Blank) T2-1-22 . SYSTEM / Control System PUMP CONTROL The pump control system has the following functions: • • • • • Speed Sensing Control Slow Speed Torque Increase Control ∗ Pump 1 Flow Rate Limit Control ∗ Pump 2 Flow Rate Limit Control ∗ Pump 3 Flow Torque Decrease Control ∗ NOTE: Only on the machines equipped with the corresponding optional parts. Pump 1 Flow Rate Limit Solenoid Valve (Optional) T178-02-01-002 T2-1-23 . Pump 2 Flow Rate Limit Solenoid Valve Max. Pump Control System Layout Pressure Sensor Travel N Sensor Pump 2 Delivery Pressure Sensor Engine Control Dial Pump 1 Delivery Pressure Sensor Pump 3 Delivery Pressure Sensor (Optional) Auxiliary(Optional) Torque Control Solenoid Valve Max. the MC sends signals to the torque control solenoid valve. controlling the pump flow rate. (Engine stall is prevented when the machine operates under adverse conditions such as operating at high altitude. the pump swash angle is reduced so that pump flow rate will be reduced. The target engine operating speed is set by controlling the engine control dial. Therefore. by which the engine output can be utilized more efficiently.SYSTEM / Control System Speed Sensing Control Function: Controls the pump flow rate in response to engine speed changes due to variations in load so that the engine output can be utilized more efficiently. The MC calculates the difference in speed between the target operating speed and the actual operating speed monitored by the N sensor. the pump swash angle is increased so that the pump flow rate will increase. The torque control solenoid valve delivers pilot pressure oil in response to the signals received from the MC to the pump regulator. 5. Flow Rate T2-1-24 Pump P-Q Curve Pressure P . 4.) Q Operation: 1. If the engine load increases and the actual engine operating speed becomes slower than the target operating speed. the engine load is reduced. If the actual engine operating speed becomes faster than the target operating speed. preventing engine stall. 2. 3. Then. ANIMATION SYSTEM / Control System N Sensor Engine Control Dial Torque Control Solenoid Valve T178-02-01-015 T2-1-25 . the pump flow rate will be reduced quickly. when traveling the machine with the engine running at slow speed. developing a shock load to the machine.SYSTEM / Control System Slow Speed Torque Increase Control Q Function: Allows the machine to travel at the maximum pump flow rate when the engine is running at slow speed. the hydraulic pump delivers pressure oil at the flow rate corresponding to point A on the P-Q curve illustrated to the right. normally. the pump P-Q curve is raised so that. if any difference exists between pump 1 and pump 2 flow rate. the MC maintains the slow speed torque increase control even if the front attachment is simultaneously operated while traveling. the machine will mistrack. 2. When the engine speed set by the engine control dial is slow. T2-1-26 Normal P-Q Curve Pressure P . increasing the pump flow rate. the pump delivers pressure oil at the flow rate corresponding to point B (maximum flow rate). the MC processes signals from the travel pressure sensor. When travel operation is made with the engine running at slow speed. and pump 1 and 2 delivery pressure sensors and sends control signals to the torque control solenoid valve. The torque control solenoid valve delivers the pilot pressure oil corresponding to the signals received from the MC to the regulator. Therefore. To prevent mistracking. Therefore. NOTE: If the MC stops the slow speed torque increase control when the front attachment is operated while traveling. Flow Rate ȀȀȀ B A Increased Torque P-Q Curve ȀȀ Operation: 1. ANIMATION SYSTEM / Control System Pressure Sensor Travel Pump 2 Delivery Pressure Sensor Pump 1 Delivery Pressure Sensor Engine Control Dial Torque Control Solenoid Valve T178-02-01-016 T2-1-27 . When a front attachment is used. The minimum pump swash setangle for a front attachment (hydraulic breaker. Operation: 1. secondary crusher. the MC receives signals from the pressure sensor (auxiliary). The minimum pump swash setangle for a front attachment (hydraulic breaker. the MC drives the maximum pump 1 flow rate limit solenoid valve (optional) to reduce the maximum pump flow rate.) Function: Limits the maximum pump 1 flow rate when a front attachment (mainly a vibrating hammer) is used.SYSTEM / Control System Pump 1 Flow Rate Limit Control (Only on the machines with the auxiliary sensor (Optional). EX. Function: Limits the maximum pump 2 flow rate when a front attachment (mainly a hydraulic breaker) is used. EX. When a front attachment is used. NOTE: In proportion to the attachment control pedal stroke. Operation: 1. the maximum pump flow rated is reduced. the MC receives signals from the pressure sensor (auxiliary). the maximum pump flow rated is reduced.) Pump 2 Flow Rate Limit Control (Only on the machines with the auxiliary sensor (Optional). Q Flow Rate Maximum flow rate is reduced. 2. Pump P-Q Curve Pressure T2-1-28 P . NOTE: In proportion to the attachment control pedal stroke. secondary crusher. 2. In response to the signals arriving from the pressure sensor. primary crusher or vibrating hammer) can be set in the service mode of Dr. the MC drives the maximum pump 2 flow rate limit solenoid valve (optional) to reduce the maximum pump flow rate. In response to the signals arriving from the pressure sensor. primary crusher or vibrating hammer) can be set in the service mode of Dr. ANIMATION SYSTEM / Control System Pressure Sensor Auxiliary(Optional) Maximum Pump 2 Flow Rate Limit Solenoid Valve(Optional) Maximum Pump 1 Flow Rate Limit Solenoid Valve T178-02-01-017 T2-1-29 . Operation: When the MC receives signals from pump 3 delivery pressure sensor (optional).) Function: Reduces pump 1 and pump 2 driving torque to prevent the engine from stalling. 2.ANIMATION SYSTEM / Control System Pump 3 Torque Decrease Control (Only on the machines equipped with pump 3 (Optional). the MC drives the torque control solenoid valve so that pump 1 and pump 2 flow rates are reduced. Q ȀȀȀ Flow Rate P-Q curve is controlled in proportion to pump 3 delivery pressure. utilizing the engine output efficiently. utilizing the engine output efficiently when the pump 3 driving torque increases. Thereby. the total pump 1. and 3 driving torque is maintained not to exceed the engine output. Normal P-Q Curve ȀȀȀȀȀ Pressure P Pump 3 Delivery Pressure Sensor Torque Control Solenoid Valve T178-02-01-018 T2-1-30 . SYSTEM / Control System (Blank) T2-1-31 SYSTEM / Control System VALVE CONTROL The valve control system functions as follows: • • • • • • Power Digging Control Auto-Power Lift Control Arm Flow Rate Control Arm Regenerative Control Travel Motor Swash Angle Control ∗ Auxiliary Flow Rate Control ∗ NOTE: Only on the machines equipped with the corresponding optional parts. T2-1-32 ANIMATION SYSTEM / Control System Valve Control System Layout Pressure Sensor Learning Switch Swing Boom Raise Arm Roll-In Auxiliary(Optional) Key Switch Pump 2 Delivery Pressure Sensor Pump 1 Delivery Pressure Sensor Engine Control Dial Power Digging Switch Hydraulic Oil Temperature Sensor Fast Pump 2 Control Pressure Sensor Slow Travel Mode Switch Pump 1 Control Pressure Sensor Solenoid Valve Unit SG SC SE SI Main Relief Valve Auxiliary Flow Rate Control Solenoid Valve (Optional) Auxiliary Flow Rate Control Valve Travel Motor Swash Angle Control Valve Arm Regenerative Valve T2-1-33 Arm Flow Rate Control Valve T178-02-01-003 SYSTEM / Control System Power Digging Control Function: Increases digging force by temporarily increasing relief pressure. Operation: For maximum 8 seconds after the power digging switch is turned ON, the MC continuously activates solenoid valve unit(SG). Solenoid valve unit (SG) delivers the pilot oil pressure to the relief valve, increasing the relief set-pressure. (Refer to the COMPONENT OPERATION / Control Valve group.) T2-1-34 ANIMATION SYSTEM / Control System Power Digging Switch Main Relief Valve Solenoid Valve Unit SG T178-02-01-019 T2-1-35 SYSTEM / Control System Auto-Power Lift Control Function: Increases oil pressure when raising the boom.) Pump 1 delivery Pressure Sensor: High pressure. (The boom must be raised to a certain extent. increasing the relief setpressure. T2-1-36 .) NOTE: This control system is activated during combined operations (except for the arm roll-in combined operation).) Operating Conditions: Boom Raise Pressure Sensor: Outputting signals. (Refer to the COMPONENT OPERATION / Control Valve group. (The control lever is in neutral. Solenoid valve (SG) delivers the pilot pressure oil to the relief valve. Arm Roll-In Pressure Sensor: Output zero. Operation: The MC activates solenoid valve unit (SG) when signals from pressure sensor (boom raise) and pump 1 delivery pressure sensor meet the following conditions. ANIMATION SYSTEM / Control System Pressure Sensor Boom Raise Arm Roll-In Pump 1 Delivery Pressure Sensor Main Relief Valve Solenoid Valve Unit SG T178-02-01-020 T2-1-37 . (Refer to the COMPONENT OPERATION/Control Valve group.) Operating Conditions: Pump 2 Delivery Pressure Sensor: High pressure. T2-1-38 .SYSTEM / Control System Arm Flow Rate Control Function: Gives pressure oil from pump 2 priority to flow to the swing motor spool over the arm 1 spool to ensure swing power. Thereby. (The swing control lever is stroked to a certain extent. the swing spool has priority. Swing Pressure Sensor: Must have some output. Solenoid valve unit (SE) delivers the pilot pressure oil to the arm flow rate control so that the parallel oil passage to the arm 1 spool is restricted. Operation: The MC activates solenoid valve unit (SE) when signals from the pump 2 delivery pressure sensor and pressure sensors (swing and arm roll-in) meet the following conditions. preventing the upperstructure from being rotated by the arm reaction force when the arm is rolled in. ensuring swing motor power.) Arm Pressure Sensor: Outputting signals. ANIMATION SYSTEM / Control System Pressure Sensor Swing Arm Roll-In Pump 2 Delivery Pressure Sensor Solenoid Valve Unit SE Arm Flow Rate Control Valve T2-1-39 T178-02-01-021 . When the arm regenerative valve is shifted. (Refer to the COMPONENT OPERATION / Control Valve group. and boom raise pressure sensor meet the following conditions.) Operating Conditions: Pump 2 Delivery Pressure Sensor: Low pressure. the return circuit from the arm cylinder rod side to the hydraulic oil tank is closed. swing pressure sensor. (The arm doesn’t need much power.) Swing or Boom raise Sensor: Outputting signal. Operation: The MC activates the solenoid valve unit (SC) so that solenoid valve delivers the pilot pressure oil to shift the arm regenerative valve when signals from the pump 2 delivery pressure sensor.) Arm Roll-In Pressure Sensor: High output. the MC gradually activates solenoid valve unit (SC) when the hydraulic oil temperature is at 0 to 10 °C (32 to 50 °F). T2-1-40 .SYSTEM / Control System Arm Regenerative Control Function: Accelerates the arm roll-in speed to prevent arm hesitation during arm roll-in operation. NOTE: To improve arm leveling performance. the return oil from the cylinder rod side is combined with the pressure oil from the pump and is routed to the cylinder bottom. Then. accelerating the arm roll-in speed and preventing arm hesitation. arm roll-in pressure sensor. (The arm control lever stroke is large. ANIMATION SYSTEM / Control System Pressure Sensor Swing Boom Raise Arm Roll-In Pump 2 Delivery Pressure Sensor Hydraulic Oil Temperature Sensor Solenoid Valve Unit SC Arm Regenerative Valve T2-1-41 T178-02-01-022 . NOTE: When one side track is raise off the ground using the front attachment and is rotated. even if the front attachment is operated (the front attachment pressure sensor is turned ON). reducing the swash angle to the minimum so that the travel speed increases.230 Operating Conditions: Travel Pressure Sensor: ON Front Attachment Pressure Sensor: OFF Pump 1 and 2 Delivery Pressure Sensor: Either pump delivery pressures are low. • ZAXIS200. the MC activates the solenoid valve unit (SI). NOTE: When one side track is raise off the ground using the front attachment and is rotated.SYSTEM / Control System Travel Motor Swash Angle Control Function: Controls the travel mode. the travel motor swash angle is kept in the maximum angle so that the travel speed is slow. the one side pump control pressure increases. • ZAXIS270 Operating Conditions: Travel Pressure Sensor: ON Front Attachment Pressure Sensor: OFF Pump 1 and 2 Delivery Pressure sensor: Both of pump 1 and 2 delivery pressure are low. allowing the raised track to rotate at fast speed.225US. Pump 1 and 2 Control Pressure Sensor: Either pump control pressures are high. T2-1-42 . Operation: When the travel mode switch is in the SLOW position.225USR. When the MC receives the signals from the travel pressure sensor. pump 1 and 2 delivery pressure sensors. the travel mode is kept unchanged in the fast mode. When the machine is traveling in the fast mode. the solenoid valve (SI) delivers the pilot pressure oil to the travel motor swash angle control valve. the one side pump displacement target angle remains small so that the travel motor speed does not increase. Then. pump 1 and 2 control pressure sensors under the following conditions with the travel mode switch in the FAST position. Pump 1 and 2 Control Pressure Sensor: Both of pump 1 and 2 control pressures are high. ANIMATION SYSTEM / Control System Pressure Sensor Travel Pump 2 Delivery Pressure Sensor Pump 1 Delivery Pressure Sensor Travel Mode Switch Fast Mode Pump 2 Control Pressure Sensor Pump 1 Control Pressure Sensor Solenoid Valve Unit SI Travel Motor Swash Angle Control Valve T178-02-01-023 T2-1-43 . boom raise.SYSTEM / Control System Auxiliary Flow Rate Control (Only on the machines equipped with the auxiliary pressure sensor and auxiliary flow rate control solenoid valve) Function: Restricts the oil flow to the auxiliary spool when the combined operation of the swing. Operation: The MC activates the auxiliary flow rate control solenoid valve (optional) so that the oil flow to the auxiliary spool is restricted under the following conditions. Operating Conditions: Auxiliary Pressure Sensor: ON Swing. and arm roll-in is made while operating a front attachment using the auxiliary spool to maintain controllability of the combined operation. Arm Roll-In Pressure Sensors: ON T2-1-44 . Boom Raise. ANIMATION SYSTEM / Control System Pressure Sensor Swing Boom Raise Arm Roll-In Auxiliary(Optional) Auxiliary Flow Rate Control Solenoid Valve (Optional) Auxiliary Flow Rate Control Valve T178-02-01-024 T2-1-45 . MC controls the boom electronic cushion solenoid valve to decrease the boom raise pilot pressure. Speed Reduction Area Position where speed reduction begins Boom Full Stroke Position T1GF-02-01-001 T2-1-46 .SYSTEM / Control System OTHER CONTROLS Boom Electronic Cushion Control (ZAXIS225US) Function: Reduces the shock which may occur when the boom reaches to its full stroke position at boom raise operation by functioning the electronic cushion in the speed reduction area. MC calculates the boom angle by this signal. When the boom angle reaches to the speed reduction area. Operation:The signal from the boom angle sensor comes into MC at boom raise operation. ANIMATION SYSTEM / Control System Boom Angle Sensor Boom Raise Boom Electronic Cushion Solenoid Valve Signal Control Valve 1 Control Valve Boom 2 1 Boom 1 1 T1GF-02-01-002 T2-1-47 . • Front Attachment Mode: Functions only when a front attachment in the optional kit is operated. digging and front attachment. T2-1-48 .SYSTEM / Control System Work Mode Control Two work modes. The engine speed (see T2-1-18 and 20) and pump flow rate (see T2-128) are controlled so as to match the installed front attachment operation in response to the movement of the auxiliary valve spool. EX. • Digging Mode: Normal control is performed. are available by operating the work mode switch. The engine speed and pump flow rate control settings are made by using Dr. Pressure Switch Travel Travel Alarm Device (Optional) Buzzer Deactivation Switch (Optional) Buzzer (Optional) T178-02-01-025 T2-1-49 . the MC sends out signals to the travel alarm device to sound the buzzer. NOTE: After traveling continuously for more than 13 seconds. the buzzer can be stopped with the buzzer deactivation switch. Operation: As long as the MC receives signals from the travel pressure sensor when travel operation is made.ANIMATION SYSTEM / Control System Travel Alarm Control (Only on the machines equipped with the travel alarm device) Function: Sounds the buzzer while traveling. SYSTEM / Control System (Blank) T2-1-50 . Main Circuit: Power Source Main Pumps Controller → Actuator → Control Valves Motors Cylinders Front Attachmens (Optional) Pilot Circuit: Power Source Pilot Pumps Controller → Pilot Circuit → Pilot Valves Operation Control Circuit Pump Regulator Pump Control Circuit Solenoid Valve Unit Valve Control Circuit Signal Control Valve Swing Parking Brake Release Circuit Boom Electronic Cushion Travel Motor Swash Angle Control Circuit ȀSolenoid Valve Hydraulic Oil Heat Circuit (Only ZAXIS225US) T2-2-1 .SYSTEM / Hydraulic System OUTLINE The hydraulic system is broadly divided into two circuits. the main circuit and the pilot circuit. SYSTEM / Hydraulic System PILOT CIRCUIT Outline: • Pressure oil from the pilot pump is used to operate the operation control circuit. travel motor swash angle control circuit. pump control circuit. T2-2-2 . and hydraulic oil heat circuit. valve control circuit. swing parking brake release circuit. ) Flow Combiner Valve Bucket Flow Rate Control Valve Regulator Boom Anti-Drift Valve Auxiliary Flow Rate Control Solenoid Valve (When the auxiliary spool is used.) Arm Anti-Drift Valve Auxiliary Flow Combiner Valve Bypass Cut Valve Auxiliary Flow Control Valve Valve Control Circuit ȳȧ Main Relief Valve ȳȣ Arm Regenerative Valve ȳȥ Arm Flow Rate Control Valve ȳȩ VC Solenoid Valve Unit Travel Motor Hydraulic Oil Tank Control Valve Suction Filter Travel Motor Swash Angle Control Circuit Travel Motor NOTE: *Boom Electronic Cushion Solenoid Valve is ZAXIS225US Only. T2-2-3 Relief Valve Pilot Filter Pilot Pump .ANIMATION SYSTEM / Hydraulic System Operation Control Circuit Travel Pilot Valve Left Pilot Valve Swing Parking Brake Release Circuit Right Pilot Valve Auxiliary Pilot Valve Boom Electronic Cushion Solenoid Valve Swing Motor Ȋ Pump Control Circuit Maximum Pump 2 Flow Rate Control Solenoid Valve Pilot ShutOff Valve Signal Control Valve Hydraulic Oil Heat Circuit Torque Control Solenoid Valve ȀȳȢ Ȁȳȴ ȀȒ ȀȀȑ ȳȡ Maximum Pump 1 Flow Rate Control Solenoid Valve (Optional) To Control Valve Spools Auxiliary Flow Combining Solenoid Valve (When the auxiliary spool is used. (Refer to the COMPONENT OPERATION / Signal Control Valve group. • The signal control valve is provided between the pilot valves and the control valve.) ZAXIS225US: • The boom electronic cushion solenoid valve is provided between the pilot valve (right) and the signal control valve on ZAXIS225US. (Refer to SYSTEM / Control System group. The shockless valve (in the boom lower circuit) built in the signal control valve dampens quick spool movement in the control valve.SYSTEM / Hydraulic System Operation Control Circuit • The pilot valves control the pressure oil from the pilot pump to operate the control valve spools.) Pilot Valve (Right) Boom Electronic Cushion Solenoid Valve Signal Control Valve T2-2-4 T1GF-02-02-001 . This valve reduces the shock which may occur when the boom reaches to its full stroke position. Left Travel Forward T2-2-5 10 .Bucket Roll-Out 9 .Boom Lower 3 .Right Travel Forward 12 .Right Swing 7 .Right Travel Reverse .Left Swing 6 .225USR.Left Travel Reverse 11 .Arm Roll-In 5 .SYSTEM / Hydraulic System ZAXIS200.Bucket Roll-In 8 .230.Arm Roll-Out 4 .270 Travel Pilot Valve Pilot Valve (Left) Pilot Valve (Right) Shockless Valve 9 10 11 12 4 3 Signal Control Valve 9 2 1 10 12 7 2 1 7 6 5 11 8 1 4 3 5 8 3 6 Control Valve Pilot Pump T178-02-02-005 1 .Boom Raise 2 . ) • Pump Flow Rate Control by Flow Rate Control Pressure Pi • Pressure oil from the pilot valve is selected by the shuttle valves in the signal control valve. bucket (roll-in/out). flow rate control pressure Pi is routed to main pump 2. and/or travel (left) function is operated. auxiliary.SYSTEM / Hydraulic System Pump Control Circuit (Refer to the COMPOMENT OPERATION / Pump Device group. arm (rollin/out). Then. • Torque Control (Speed Sensing) by Torque Control Solenoid Valve • After the pilot oil pressure from the pilot pump is regulated by the torque control solenoid valve. T2-2-6 . When the boom (raise/lower). arm (rollin/out). NOTE: When the boom (raise/lower). swing (right/left). and/or travel (right) function is operated. the selected pressure oil is routed further to either the pump 1 flow rate control valve or the pump 2 flow rate control valve in the same signal control valve. flow rate control pressure Pi is routed to main pump 1. the regulated pilot oil pressure is routed to main pump 1 and 2 as speed sensing pressure Ppc. shifting either of the flow rate control valves. the pilot pressure oil from the pilot pump is routed to either main pump 1 or main pump 2 as flow rate control pressure Pi. • When either the pump 1 flow rate control valve or the pump 2 flow rate control valve is shifted. ANIMATION SYSTEM / Hydraulic System Travel (Left) Swing Travel (Right) Arm Boom Bucket Signal control Valve Pump 1 Flow Rate Control Valve Pump 2 Flow Rate Control Valve Control Valve Torque Control Solenoid Valve Pilot Pump Pump 2 Pump 1 T178-02-02-006 T2-2-7 . ) • Solenoid Valve SC: Arm Regenerative Valve • Solenoid Valve SE: Arm Flow Rate Control Valve • Solenoid Valve SG: Main Relief Valve (increasing the set-pressure) • Auxiliary Flow Rate Control Solenoid Valve: Auxiliary Flow Rate Control Valve (When the auxiliary spool is used.) • Auxiliary Flow Combining Solenoid Valve: Boom. solenoid valve unit (SC. and the bucket flow rate control valve control spool. and SG).SYSTEM / Hydraulic System Valve Control Circuit (Refer to the COMPONENT OPERATION / Control Valve and Travel Device groups. • Boom Lower Pilot Pressure: Boom Anti-Drift Valve • Arm Roll-In Pilot Pressure: Arm Anti-Drift Valve • Auxiliary Pilot Pressure: Auxiliary Flow Combiner Valve. the flow combiner valve control spool in the signal control valve. Bypass Shut-Out Valve (When the auxiliary spool is used. and Bucket Pilot Pressure • Flow Combiner Valve Control Spool: Flow Combiner Valve • Bucket Flow Rate Control Valve Control Spool: Bucket Flow Rate Control Valve T2-2-8 . SE. Arm.) • The following valves are controlled by pressure oil from the pilot valves. SYSTEM / Hydraulic System Travel (Right) Arm Roll-In Boom Lower Auxiliary Signal Control Valve 4 2 Main Relief Valve Auxiliary Flow Rate Control Valve Auxiliary Flow Combining Solenoid Valve Flow Combiner Valve Control Spool Bucket Flow Rate Control Valve Control Spool Auxiliary Flow Combiner Valve Flow Combiner Valve Auxiliary Flow Rate Control Solenoid Valve Bucket Flow Rate Control Valve Arm Anti-Drift Valve 2 Solenoid Valve Unit Boom Anti-Drift Valve 4 SG SC SE Bypass Shut-Out Valve Pilot Pump Arm Regenerative Valve Arm Flow Rate Control Valve T178-02-02-007 T2-2-9 . T2-2-10 . the pilot oil pressure selected by the shuttle valves in the signal control valve shifts the swing parking brake release spool. • Consequently. Travel Motor Swash Angle Control Circuit (Refer to the COMPONENTS OPERATION / Travel Device group. releasing the swing parking brake.) • When the pilot shut-off valve is closed. the release signal oil pressure is routed to the swing motor.) • When the front attachment and/or swing function is operated.SYSTEM / Hydraulic System Swing Parking Brake Release Circuit (Refer to the COMPONENTS OPERATION / Swing Device group. • The warmed pilot pressure oil flows to the signal control valve and pilot valves so that the pilot system components are warmed.) • The pilot oil pressure from solenoid valve SI regulates the travel motor swash angle control valve. the pilot oil pressure is routed to the signal control valve so that hydraulic oil is warmed while passing through the orifice in the signal control valve. Hydraulic Oil Heat Circuit (Refer to the COMPONENTS OPERATION / Others (Upperstructure) group. SYSTEM / Hydraulic System Swing Arm Boom Bucket Orifice Signal Control Valve Swing Parking Brake Release Spool Solenoid Valve Unit Swing Motor Control Valve SI Travel Motor T178-02-02-008 Swash Angle Control Valve T2-2-11 . Main pump 1 and main pump 2 deliver pressure oil to the 4-spool control valve and the 5-spool control valve respectively.SYSTEM / Hydraulic System MAIN CIRCUIT Outline • Main pumps (1 and 2) draw hydraulic oil from the hydraulic oil tank. T2-2-12 . allowing hydraulic oil to return directly to the hydraulic oil tank without passing through the oil cooler. • Delivered pressure oil is routed to the motor(s) or cylinder(s) in response to operation(s) of the spool(s) in the control valve(s). which opens the bypass check valve. • When the oil temperature is low (high viscosity). • The return oil from the motor(s) and/or cylinder(s) flows back to the hydraulic oil tank via the control valve and/or the oil cooler. the oil flow resistance increases in the oil cooler. ANIMATION SYSTEM / Hydraulic System Travel Motor (Left) Travel Motor (Right) Bucket Cylinder Front Attachment (s) Control Valve Boom Cylinder 4-Spool Side Arm Cylinder Travel (Left) Travel (Right) Auxiliary Bucket Boom 2 Boom 1 Arm 1 Arm 2 Swing 5-Spool Side Bypass Check Valve Swing Motor Oil Cooler Main Pump 2 Main Pump 1 Suction Filter T2-2-13 Hydraulic Oil Tank . • Pressure oil from main pump 2 is routed to the 5spool control valve and is further routed to each spool of the swing. Single Operation Circuit • Pressure oil from main pump 1 is routed to the 4spool control valve and is further routed to each spool of the travel (right). and travel (left). T2-2-14 . boom 2. bucket. pressure oil from the main pump passes through the control valve and returns to the hydraulic oil tank. • The boom and arm are actuated by pressure oil from two main pumps. Pressure oil from each main pump is combined and supplied together.SYSTEM / Hydraulic System Neutral Circuit • When the control lever is in neutral. boom 1. arm 1. and arm 2. ANIMATION SYSTEM / Hydraulic System Travel Motor (Left) Travel Motor (Right) Control Valve Travel (Left) Front Attachment Travel (Right) Bucket Cylinder Auxiliary Bucket Arm Cylinder Boom 1 Boom Cylinder Boom 2 Swing Motor Arm 1 Arm 2 Swing 5-Spool Side 4-Spool Side Pump 2 Pump 1 T178-02-02-001 T2-2-15 . • Pressure oil from pump 2 flows into the swing motor via the swing spool. • At the same time. T2-2-16 . • Pressure oil from pump 1 flows into the boom cylinders via the parallel circuit and the boom 1 spool. and boom 2 spools.SYSTEM / Hydraulic System Combined Operation Circuit • Swing and Boom Raise Operation • When the boom is raised while swinging. boom 1. raising the boom together with pressure oil from pump 1. flows into the boom cylinders. the pilot oil pressure shifts the swing. raising the boom. pressure oil from pump 2 flows through the parallel circuit and after being combined with pressure oil from pump 1. ANIMATION SYSTEM / Hydraulic System Parallel Circuit Boom 2 Boom 1 Boom Cylinder Swing Motor Swing Parallel Circuit Pump 2 Pump 1 T178-02-02-002 T2-2-17 . the right travel pilot oil pressure shifts the flow combiner valve control spool in the signal control valve. ensuring that the machine can travel straight. T2-2-18 .Ȁ pressure oil from pump 1 passes through the flow combiner valve and the left travel spool and drives the left travel motor. shifting the flow combiner valve. • Pressure oil from pump 2 flows into the arm cylinder via the arm 1 spool. • At the same time. arm 1 and 2 spools. the pilot oil pressure shifts the travel. pressure oil from pump 2 is used only to operate the arm. moving the arm. • Pressure oil from pump 1 drives the right travel motor via the right travel spool. • Consequently. Pressure oil pump 1 is equally routed to both the right and left travel motors.SYSTEM / Hydraulic System • Travel and Arm Roll-In Operation • When the arm is rolled in while traveling. • At the same time. Pressure oil from the flow combiner valve control spoolȀis routed to the flow combiner valve. ANIMATION SYSTEM / Hydraulic System Pilot Pressure Oil from Flow Combiner Valve Control Spool in Signal Control Valve Travel Motor (Left) Left Travel Travel Motor (Right) Right Travel Arm Cylinder Arm 1 5-Spool Side Pump 2 4-Spool Side Pump 1 T178-02-02-003 T2-2-19 . (Refer to the SYSTEM / Control System group. and/or right travel operation. T2-2-20 NOTE: During boom (raise or lower). arm (roll-in or roll–out).) . • Therefore. the neutral circuit in the 4-spool control valve is blocked so that pressure oil from pump1 is routed to the auxiliary spool via the auxiliary flow combiner valve. pilot pressure oil is routed to port SN from the signal pilot pressure control valve so that the aux. flow combiner valve is not shifted. the pilot pressure oil from the hydraulic breaker pilot valve shifts the auxiliary flow combiner valve and bypass shut-out valve.SYSTEM / Hydraulic System Auxiliary Circuit • When a front attachment such as a hydraulic breaker is operated. bucket (roll-in or roll–out). ANIMATION SYSTEM / Hydraulic System Pilot Oil Pressure from Hydraulic Breaker Pilot Valve Auxiliary Flow Combining Solenoid Valve Auxiliary Flow Combiner Valve Pilot Pressure from Signal Control Valve SN SM Front Attachment Neutral Circuit Auxiliary Bypass Cut Valve Pump 2 Pump 1 T178-02-02-004 T2-2-21 . SYSTEM / Hydraulic System (Blank) T2-2-22 . and displays the machine operation status. • Main Circuit The engine and accessory operation related circuit. sensors. and switches.SYSTEM / Electrical System OUTLINE The electrical circuit is broadly divided into the main circuit. monitor circuit.) The control circuit is categorized into the engine. • Monitor Circuit The electrical circuit group consists of the monitors. T2-3-1 . Each circuit consists of the actuators such as solenoid valves. sensors and pressure switches. and control circuit. and valve control circuits. • Control Circuit (Refer to the SYSTEM / Control System group. switch boxes. pump. MC (main controller). [MC. Fuses (Fuse Boxes. QOS Controller. Starter Relay] • Charging Circuit Charges the batteries. Regulator] • Serge Voltage Prevention Circuit Prevents the occurrence of serge voltage developed when stopping the engine. • Electric Power Circuit: Supplies all electric power to all electrical systems on this machine. [Key Switch. Glow Plug Relay. Starter. [Key Switch.SYSTEM / Electrical System MAIN CIRCUIT The major functions and circuits in the main circuit are as follows. [Key Switch. Battery Relay] • Indicator Light Check Circuit Checks all indicator bulbs for burning. Glow Plugs] • Starting Circuit Starts the engine. Batteries. • Preheat Circuit Assists the engine to start in cold weather. Fusible Links). [Load Damp Relay] • Engine Stop Circuit Stops the engine using the EC motor. [Alternator. • Accessory Circuit Becomes operative when the key switch is turned to the ACC position. EC Motor] T2-3-2 . Coolant Switch. ANIMATION SYSTEM / Electrical System ELECTRIC POWER SWITCH: OFF) CIRCUIT (KEY The battery ground terminal is connected to the vehicle frame. Battery ↓ Fusible Link →Glow Plug Relay ȈPowerȉ →Terminal #1: Radio (Backup Power) Monitor (Backup Power) →Key Switch (B) →Load Damp Relay →Fuse Box ICX Controller (Backup Power) →Terminal #2: MC (Power) →Terminal #3: MC (EC Motor Power) →Terminal #10: Optional Key Switch Battery Load Damp Relay Glow Plug Relay Radio. Monitor. ICX Controller Optional MC MC T178-02-03-001 T2-3-3 . Current from the battery plus terminal flows as shown below when the key switch is OFF. ANIMATION SYSTEM / Electrical System INDICATOR LIGHT CHECK CIRCUIT (KEY SWITCH: ON) • When the key switch is turned ON. the battery current enters the monitor controller via the battery relay and fuse #6 and checks the indicator bulbs. terminal B is connected to terminals ACC and M in the key switch. • Current from key switch terminal M excites the battery relay. Key Switch Battery Battery Relay Fuse Box Monitor Controller T178-02-03-002 T2-3-4 . • Therefore. Fuse Box Horn Radio Lighter Cab Light Auxiliary T178-02-03-003 T2-3-5 . lighter (fuse #16). • Current from key switch terminal ACC flows to horn (fuse #14). making each accessory operable. terminal B is connected to terminal ACC in the key switch. cab light (fuse #17) and auxiliary (fuse #18) through the fuse box. radio (fuse #15).ANIMATION SYSTEM / Electrical System ACCESSORY CIRCUIT • When the key switch is turned to the ACC position. . heating will continue for approx. • Accordingly. QOS controller terminal #4 is connected to terminal #5 (ground). 30 seconds after the engine starts. the preheat indicator comes ON for 2 seconds for indicator light check. turning the preheat indicator ON. • When preheating begins.SYSTEM / Electrical System PREHEAT CIRCUIT (KEY SWITCH: ON / START) • When the key switch is turned ON or to the START position. routing current to the glow plugs so that preheating begins. • When the key switch is ON or in the START position with the coolant switch OFF (when the coolant temperature is 10 °C (50 °F) or below). Current from terminal M is routed to QOS controller terminal #1 through fuse #19. (When preheating is not performed. terminal B is connected to terminal M in the key switch. QOS controller terminal #6 is connected to terminal #5 for 8 seconds. the glow plug relay is turned ON.) T2-3-6 NOTE: After preheating has been performed. ANIMATION SYSTEM / Electrical System Monitor Coolant Temperature Switch Preheat Indicator QOS Controller Key Switch Fuse Box Glow Plug Relay Glow Plug T178-02-03-004 T2-3-7 . Condenser C1 is used to stabilize the operating voltage and diode D4 protects the circuit in case the battery terminals are reversely connected. • Then. key switch terminal B is connected to terminal ST so that current is routed to the base in transistor (Q2) through resistance R4 in the starter relay. • On the other hand. the relay in the starter is turned ON so that the starter begins rotating. • After the engine starts. • Consequently. battery current is routed to starter terminal B and starter relay terminal B via the battery relay. Then. allowing current to flow to coil (L) in the starter relay. the MC drives the EC motor. transistor (Q2) is turned ON.ANIMATION SYSTEM / Electrical System STARTING START) CIRCUIT (KEY SWITCH: • When the key switch is turned to the START position. Therefore. increasing voltage at starter relay terminal R. Starter Relay Operation • When the key switch is turned to the START position. • As soon as the MC receives this signal. rotating the starter. Zener diode (Z) is turned ON so that transistor (Q1) is turned ON. Starter Relay ȳ Ȣ Ȥȓ Ȉȑȉ Ȭ ȲȔ Ȳȓ To Alternator Terminal L Ȳ Ⱥ ȲȒ ȈȒȉ ȤȒ ȱȑ ȣ Ȉȑȉ ȭ ȱȒ ȣ Ȣ ȈȒȉ ȥ ȤȔ ȣȑ ȣ Starter Ȣ ȑȒȶ ȳȴ Key Switch ȑȒȶ Battery T107-04-04-003 T2-3-8 . the starter relay is turned ON. At this moment. current from key switch terminal M flows to the MC via fuse #6 as a signal indicating that the key switch is in the ON or START position. moving the governor lever to the engine start position. terminal B is connected to terminals M and ST in the key switch. allowing current to flow from starter relay terminal C to starter terminal C. current to the base of transistor (Q2) is not routed. • Key switch terminal ST is connected to starter relay terminal S so that current flows through the starter relay coil. • As current from terminal M excites the battery relay. the alternator starts generating electricity. turning transistor (Q2) OFF. Then. stopping the starter. • When this voltage increases up to 21 to 22 V. starter terminal B is disconnected from terminal C. starter terminal B is connected to terminal C. ANIMATION SYSTEM / Electrical System Key Switch Battery Battery Relay Fuse Box Starter C C Starter Relay EC Motor MC T178-02-03-005 T2-3-9 . • Then. turning the alternator indicator OFF. • When the alternator starts generating electricity.ANIMATION SYSTEM / Electrical System CHARGING CIRCUIT (KEY SWITCH: ON) • After the engine starts and the key switch is released. current flows from alternator terminal B to the batteries via the battery relay. charging the batteries. key switch terminal B is connected to terminals ACC and M in the key switch. • Current from alternator terminal L flows to the monitor controller and the ICX controller. Key Switch Battery Monitor Controller ICX Controller Battery Relay Alternator T178-02-03-006 T2-3-10 . the key switch moves to the ON position. SYSTEM / Electrical System (Blank) T2-3-11 . the rotor is further magnetized so that the generating voltage increases. the battery voltage is applied to base B of transistor T1 so that collector C is connected to emitter E. Zener diode ZD. Thereby. stator coil SC. Therefore. • When current starts to flow through field coil FC. • At the beginning. The regulator consists of transistors (T1 and T2). alternate current is generated in stator coil SC by the rotor remanent magnetism. no current is flowing through field coil FC. • Alternator terminal B is connected to base B of transistor T1 through the circuit [B → R → RF → ( R ) → (R1)]. current flowing through field coil FC increases and generating voltage is increased further. to charge the batteries.ANIMATION SYSTEM / Electrical System Alternator Operation • The alternator consists of field coil FC. field coil FC is grounded via transistor T1. Alternator Ȣ Ȣȳ Ȳ ȲȦ Regulator Ȭ ȈȲȉ Ȳȓ Ȳȕ ȲȔ ȲȖ Ȥ ȺȤ ȲȒ Battery Ȣ ȳȣ ȥ Ȳȑ Ȧȣ Ȥȑ ȣ Ȣ ȣ ȴȒ ȥ ȴȑ ȈȦȉ ȥ Ȉȥȉ T157-04-02-008 T2-3-12 . and resistances (R1 and R2). • When battery relay BS is ON. When the rotor starts turning. and diodes D. current is routed to base B of transistor T2. The above operation is repeated so that the alternator generating voltage is kept constant. reducing generating voltage at stator coil SC. increasing generating voltage at the stator coil.ANIMATION SYSTEM / Electrical System Regulator Operation • When generating voltage increases more than the set-voltage of Zener diode ZD. • Therefore. turning transistor T1 OFF. no current flows through filed coil FC. current which was routed to base B of transistor disappears. • When generating voltage decreases lower than the set-voltage of Zener diode ZD. Ȣȳ ȲȦ Ȳȓ ȲȔ Ȳȕ ȲȖ Battery ȺȤ ȲȒ Ȣ ȳȣ ȡ ȥ ȣ Ȧȣ Ȳȑ Ȣ ȣ ȴȒ ȥ ȴȑ ȈȦȉ ȥ Ȥȑ Ȉȥȉ T157-04-02-009 T2-3-13 . • Then. causing transistor T1 to turn ON again. transistor T2 is turned OFF. connecting collector C to emitter E. • Then. current flows through field coil FC. current flows through the load damp relay exciting circuit. T2-3-14 • When the alternator is generating electricity. allowing the generating current to flow to the batteries. • The engine continues to rotate due to inertia force just after the key switch is turned OFF so that the alternator continues to generate electricity. . possibly causing failures of the electronic components. To prevent the occurrence of surge voltage. • Then. the surge voltage prevention circuit is provided. even if the key switch is turned OFF while the engine is rotating. Therefore. the battery current continues to excite the battery relay via the load damp relay until the alternator stops generating. the battery relay is kept ON. such as the controller. surge voltage arises in the circuit. • Accordingly. generating current from alternator terminal L flows to monitor controller terminal #A-2 so that the monitor controller connects terminal #C-3 to ground. turning the load damp relay ON.SYSTEM / Electrical System SERGE VOLTAGE PREVENTION CIRCUIT • When the engine is stopped (key switch: OFF). • As the generating current cannot flow to the battery. turning the battery relay OFF. current from key switch terminal M is disconnected. ANIMATION SYSTEM / Electrical System Key Switch Battery Battery Relay Load Damp Relay Alternator Monitor Controller T178-02-03-007 T2-3-15 . the signal current indicating that the key switch is ON stops flowing from terminal M to MC terminal C-31. the MC drives the EC motor to the engine stop position. • Then. Key Switch EC Motor MC T178-02-03-008 T2-3-16 .ANIMATION SYSTEM / Electrical System ENGINE STOP CIRCUIT • When the key switch is turned from the ON position to the OFF position.