1 Overview
The controller has a backup system for operator dry operation. When there is a problem with the electronic control system, the operator can activate the backup system to control the size of the main spring and the engine throttle. The backup system consists of a backup device for the governor that controls the engine speed and a backup device for the main pump. When there is a problem with the electronic control system that controls the governor, the operator can activate the governor backup device, and when there is a problem with the electronic control system that controls the main pump, the operator can activate the main pump backup device
During the use of the main pump backup device, the output power of the main spring is equivalent to the output power when the power mode or Ⅱ is selected
2. Working principle of standby system
The circuit diagram of the standby system is shown in Figure 4-93.
When the controller works normally, the standby system must not be used. At this time, the governor 3 is powered by the governor drive circuit 4, and the proportional pressure reducing valve 7 is powered by the proportional pressure reducing valve drive circuit 8. At this time, the main pump is regulated normally.
The governor backup switch 2 and engine speed change switch 5 are located at the rear end of the right console, and the main pump backup switch 6 is located at the rear end of the left console. When the controller stops working, the governor backup switch should be in the AUTO position At this time, the engine speed change switch 5 is in the idle position, and the main pump standby switch 6 is in the AUTO position.
The backup device of the governor and the main pump can be controlled separately
3. Spare device for governor
If there is a problem with the controller, the digital display will not show the value of the engine throttle knob. When this happens, the governor backup switch should be used to clear the display function of the controller, and the engine speed change switch should be used to adjust the engine speed.
During the operation of the backup device of the governor, the digital display will show the English letters A or U. When only the governor standby switch is used alone, display A; when the governor standby switch and the main pump standby switch are used at the same time, display U: When there is a problem with the governor drive circuit, the digital display will show the same information , So pay special attention during use, and don't mistake this for the display of the backup device. The governor standby device is controlled by the governor standby switch 2 and the engine speed change switch 5.When the governor standby switch 2 is in the manual operation (MAN) position, move the engine speed change switch 5 in the fast direction, the engine speed Raise the engine speed change switch 5 to the slow speed direction, lower the engine speed, release the engine speed change switch 5 to keep the engine speed at the previously selected speed, then the governor backup device cancels the engine throttle knob Function.
4. Main pump spare river device
When there is a problem with the main pump control part of the controller, the controller warning indicator or excavator warning indicator is on, or the controller indicator appears yellow or red: when this happens, the main pump standby switch should be turned 6. When the main pump standby liver switch is turned to the slow ("black") position, the circuit between the proportional pressure reducing valve 7 and the controller is disconnected. At this time, the proportional pressure reducing valve 7 is powered by the power supply and is formed with the standby resistor 10 The current passing through the solenoid coil of the proportional pressure reducing valve is constant current. The power conversion pressure of the main pump output by the proportional pressure reducing valve is also constant, and the controller obtains the standby signal that the standby switch has used.
During the operation of the main pump standby switch, the digital display shows the following symbol, H: indicates that only the main pump standby switch is used.
