1, mechanical oscillation (acceleration/deceleration)
Common causes of such failures are:
① Pulse encoder failure. At this time, it should be checked whether the voltage on the feedback line terminal of the speed detection unit drops at a certain point. If there is a drop, the pulse encoder is bad and the encoder should be replaced.
② The cross coupling of pulse encoder may be damaged, resulting in the shaft speed being out of sync with the detection speed, so replace the coupling;
③ Fault of tachogenerator. Repair and replace the tachometer. In the maintenance practice, the electromechanical brush of tachometer often appears wear and jamming faults. At this time, it is necessary to remove the brush of tachometer, polish it with steel sandpaper for several times, clean up the dirt of commutator, and reinstall the servo motor.
2, the mechanical movement is extremely fast (flying)
For this kind of fault, in addition to checking the position control unit and speed control unit, it is also necessary to check: ① whether the wiring of pulse encoder is wrong; ② Whether the coupling of pulse encoder is damaged; ③ Check whether the terminal servo motor of tachogenerator is connected reversely and whether the excitation signal line is connected wrongly.
3, the spindle can't directional movement or directional movement is not in place.
For this kind of fault, check whether the output waveform of the position detector (encoder) is normal while checking the setting adjustment of the direction control circuit, the adjustment of the direction plate and the adjustment of the spindle control printed circuit board (note that the normal output waveform of the encoder should be recorded when the equipment is normal, so as to check correctly when the fault occurs).
4. Vibration when the coordinate axis is fed
Check the motor coil, mechanical feed screw and motor connection, servo system, pulse encoder, coupling and tachometer.
5. An NC error alarm appears
Alarm caused by program error and operation error in numerical control alarm. For example, the Nc of FANUC6ME system gives an alarm of 090.05438+0, which may be due to: ① main circuit failure and low feed speed; ② Bad pulse encoder; ③ The power supply voltage of the pulse encoder is too low (at this time, adjust the voltage of the power supply 15V to make the voltage on the +5V terminal of the main circuit board between 4.95-5. 10V); (4) The input pulse encoder does not have a loop signal, so the reference point cannot be returned normally.
6, servo system alarm
When the servo system fails, the following alarm numbers often appear, such as 4 16, 426, 436, 446 and 456 servo alarms of FANUC6ME system; STEMENS880 system 1364 servo alarm; At this time, we should check the servo alarm of STEEMENS8 system, such as 1 14, 104:① The feedback signal of the axial pulse encoder is broken, short-circuited and lost, and use the conversion indicator to measure whether the phase A and phase B signals are normal; (2) The encoder has an internal fault, which leads to the signal not being received correctly. Check whether it is polluted, too dirty or deformed.
(1) OH alarm for Siemens servo motor maintenance. OH is the overheat alarm of the speed control unit, and the possible reasons for this alarm are:
① The setting of S 1 on the printed circuit board is incorrect.
② The servo unit is overheated. When the thermal switch on the radiator acts, when the driver has no hardware damage or defect, the alarm can be eliminated by changing the cutting condition or load.
③ The regenerative discharge unit is overheated. Q 1 may be defective. When there is no hardware defect in the driver, the load can be reduced and the alarm can be eliminated by changing the acceleration and deceleration frequency.
④ The power transformer is overheated. When the transformer and temperature detection switch are normal, the load can be reduced, the alarm can be eliminated, or the transformer can be replaced by changing the cutting conditions.
⑤ The overheat switch of the radiator of the electric cabinet acts, because the electric cabinet is overheated. If the switch still works at room temperature, the temperature detection switch needs to be replaced.
(2) Fault alarm for Siemens servo motor maintenance. The parameter setting of digital servo is wrong, so it is necessary to change the setting of related parameters of digital servo. For FANUC0 system, the relevant parameters are 8 100, 810, 8 12 1, 8 122, 8 123 and 8/kloc. For the system10/112/15, the relevant parameters are 1804, 1806, 1875.
(3) FBAL alarm is used for the maintenance of Siemens servo motor. FBAL is an alarm for wrong connection of pulse encoder. Alarm usually has the following reasons:
① The encoder cable connection is poor or the pulse encoder itself is poor.
② The signal of external position detector is wrong.
③ The detection loop of the speed control unit is bad.
④ The gap between motor and machinery is too large.
(4) Servo Driver Alarm The 7-segment nixie tubes on FANUCC series and α/αi series digital AC servo drivers usually display stateless indicator lights, and the driver alarm is displayed through the 7-segment nixie tubes on the drivers. According to the different state display of 7-segment digital tube, the driver can be indicated the reason of alarm.