1、the main motors of hydraulic pump cannot start
Check and analyze: push the start buttons of hydraulic pump to investigate if contactor of hydraulic pump has contacts with each other or not.
1）if contactor is not contacts with each others.
A、if thermo relay has been operated or not and whether has been damaged or not
B、the voltage of power is normal or not(check by multimeter).
C、check the start and stop buttons operate normally whether control lines has been shorted or not.
D、whether contact coils has been damaged or not (check by multi meter ).
2) If contactor contact with each other’s then check：
A、If the hydraulic pump has damaged or assembled too tight or not, rotate the Shafter by hand, the Shafter should have a 3~5mm of level of gaps.
B、Whether the line connect between the 3 phase power and motors.
C、If the main motor has been damaged or not.
2、 press pump start button，thermorelay tripping operate
check and analyze：Push the start buttons of hydraulic pumps, after running of main motor for times, the thermo relay will be tripping operation (be off).
1）hydraulic relay has bee damaged or rated current is too small（especially pay attention to the start of using Y-△ start the position of thermo relay are different in main circuit, should adjust the rated current).
2）current has increased because of the voltage is too low or imbalance of voltage of 3 phase .
3）the resistance of the wire windings of 3 phase of main motor is unbalanced.
4）main pressure and the pressure of double pump has been adjusted with too highly and caused switch became “off” with that the machine was running with too larger load.
5）hydraulic pump has been damaged or been assembled with too tight.
check analyze：after starts hydraulic pumps, push the pressure start button looking at whether has current of system pressure and flow valve or not ,be sure that whether it is electronically,or is the failure of hydraulic.
1） if has the current output then check:
A、whether the hydraulic pump rotating by reversely or not (along to the direction of shaft of hydraulic pump the clockwise rotation is correct）.
B、check whether the overflow valve is adjusted with improperly or check up.
C、check whether the relief valve been closed or not.
D、whether the first speed of injection. The second speed of injection cartridge valve been opened or not, the controller of pressure increasing valve is normal or not.
E、pressure meters has been damaged or not , whether is the miss indicating or not.
2) if no current output and then check：
A、whether the rectify power is normal or not ,the system pressure and flow amplifier board is adjust with improper or damaged.
B、be sure with that the operation of PLC is normal or not
C、check switch of air counter is normal or not.
4.Auto mode failure
if the manual mode is normal but no auto mode movement ,to check whether the safety door limit switch is normal or not, and the movement is back to the origin point or not （in accordance with the requirement of operation of machine ）before running with auto mode should satisfy the condition below ：safety door(both front and back door) Closed signal input lamp is placed in “on”；Auto signal input lamp is placed in ‘on”, ejector returns backs to limit signal input lamp is placed in “on”. If manual operate mode is abnormal should find the root cause and check and sweep the failure out.
5.Die height adjustment unavailable
Check and analyse: selecting die height adjustment mode to operate, if die height adjustment is unavailable, check as the following steps:
1）whether the conditions for the mould adjustments been satisfied or not, for example the die height thin requires: Die height thin button have input, die height thick button have no input, two die height limit positions have inputs.
2）the setting value of mould adjustment is too low or not.
3）manual operate mode is correct or not.
5）if the content above have no problem and to check the items below：
A、whether the mould adjustment of hydraulic motor has been check up or not, damaged or not.
B、whether the core of hydraulic valve of mould adjustment has been checkup or not.
C、in the every moving parts to the mould adjustment to be warned or not. And check up or not.
check and analyse：after starting the hydraulic pump, manual mode, auto mode has no movements,then push the pressure button to check whether the machine has pressure or not.
1） if no pressure to check ：
A、voltage stabilizer been damaged or not and fuse tube is burned down or not.
B、system pressure and flow proportional control board input and output are normal or not.
C、check the adjustment to the system pressure and flow proportional valve is proper and not damaged or not
D、the PLC is working normal or not .
E、the system pressure setting is proper or not.
2） if have pressure to check：
A、all the connects of oil valve is been normal.
7.die can’t close
Check and analyze: close safety door properly and push the two mould close buttons. if has no signal output then check：
A、check the inputs of PLC is correct ,the two die close buttons should have input, mould open button has no input, the signal of ejector returning back to origin position has input, the core pulling had select or not, if select, the core pulling limit switch should be in right position, no input for the mould close end. If no the signals of input then check with outer wire connecting.
B、if the conditions of mould close are satisfied without the signal output for mould close. Then is the failure of PLC.
1） PLC have signal of output then to check with ：
A、 Mould close pressure is normal or not, pushes the pressure test button and look at the pressure from the pressure meter.
B、 Be sure that the wiring connects of die close between electrical box and oil valve is correct or not, and magnetic coils of mould close is normal.
C、 Hydraulic pump is damaged or not.
8.No normal speed die close
Check and analyze: observe PLC whether have normal speed input and output.
1） If PLC no normal speed input, then check whether the circuit from normal speed knob switch to PLC is normal or not.
2） If PLC has input signal but no output, it is PLC error.
3） If PLC has input and output, then check:amplifier board work normal or not, circuit from amplifier board to the valve is normal or not, valve coils damaged or not.
4） Normal speed valve core jammed or too less flow, valve speed adjusts OK or not.
9.die cannot open
check and analyze：Firstly check the die open button to check the main PLC has the inputs and outputs.
1）checking items for no signal of output:
A、mould open button has no input, if any core pulling has been select, the core limit switch should be right positions
B、the signal of manual mode should be on, and the die open button signal is also on, otherwise should check the wiring connecting between the mould open buttons
2）if PLC working well then check.
A、amplifier board work properly .
B、the connect line from amplifiers to oil valve is normal, if the oil valve has damaged or not.
C、the valves for mould open has jammed up with something.
D、the pressure of mould opening is normal（look at pressure meters）.
E、sudden electricity stop for long time after mould close,may cause the mould open not work. you should adjusting the system pressure to the max.selects high speed mould open and push pressure test button down and push the button of mould open to proceed with the movement of mould open .
G、checking the hydraulic pump of mould open and mould close has no serious oil leakage.
check and analyze:With manual mode the plunger movement is ok, but with auto mode there is no shooting movement, then check the item below:
1）if the knob of manual/auto mode is normal:
A、the signal for die close end has no input.:The limit switch for confirm of die close has no proper cooperation. The proximity switch for ending of die close has inducted, but the limit switch for the confirm of ending of die close has not been pressed, or the limit switch has broken.
B、proximity switch for ending of shooting has been damaged.
C、if the first speed of shooting ,the valve for the plunger back warding has conducted, if the core of valve has been operate.
D、shooting time is too short.
E、the hydraulic cylinder for shooting has damaged.
F、the hydraulic system has no pressure.
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