unset multi paper path printer electrical troubleshooting examples
our factory has an unset multi paper path printer, which is driven by two 90kw DC motors. During the printing process, the two motors must maintain the same speed. Therefore, each motor has a speed measuring motor coaxially connected with the main motor. According to different rotating speeds of the main motor, the speed measuring motor will generate the corresponding 0 ~ 10V DC voltage and feed it back to the main motor control system, so as to maintain the complete consistency of the speed from the imaging and qualitative and quantitative characterization of the material microstructure
recently, a motor vibrated during the printing process, and a large noise was emitted from the transmission belt. Open the cover at the transmission belt and find two V-belts with large wear. After replacing and adjusting the belt preload, the noise was reduced a little, but it could not be eradicated. In the process of continuing to use, the phenomenon of the printing press crawling at low speed appeared. Judging from this phenomenon, there may be a problem with the synchronization of the two DC motors. Disconnect the two motors from the transmission wheel belt and let the motor idle. The results show that the armature voltage of the two motors is quite different, one is 80V, the other is 300V, and the actual speed of the motor is also quite different. Judging from the above phenomena, because the output of the speed measuring motor is not the most perfect voltage, there is a problem, which leads to the calculation error of the control system. Different armature voltages are output to the two motors, so that the motors are not synchronized. There is always a motor with faster speed to drive the printing press, while the other motor is only driven to rotate. If the torque of the low-speed motor is small, crawling will occur; At high speed, due to the large speed difference, it will aggravate the wear of the motor belt with slow speed and make noise. Check the speed measuring motor. It is found that the rotor bearing and brush are seriously worn. The fault is eliminated after replacing the speed measuring motor
(text/Wang Wei Jinan printing plant)
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