Fault diagnosis of the main motor of the hottest H

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Fault diagnosis of main motor of Heidelberg 102v offset press

our factory introduced a Heidelberg 102v-4 split four-color offset press in 1990. Since the end of 2001, the machine often has the phenomenon of normal inching but no operation, and then it is powered on after power failure, and then it operates normally with d=h plus 0-h. By February, 2002, this phenomenon occurred frequently, which made the machine unable to produce normally. The specific performance is:

(1) the inching is normal

(2) press the run button for the first time to start the alarm, and the paper receiving chain obviously moves forward; Press the run button for the second time, and the machine will not start

(3) the CP window of the console shows that the braking part of the main motor is faulty

after nearly a week of analysis and treatment, we finally found out the cause of the fault. Now the analysis process is introduced as follows

1. Remove the wiring of the brake electromagnet, press and hold the operation button, and the measured input voltage of the electromagnet is 23.8v, which is within the normal range (23.7 ~ 24V), indicating that the input circuit is normal, so it can be judged that the problem may be in the motor braking part

2. Measure the resistance at both ends of the electromagnet coil, which is 5 Ω, to prove that the coil is not damaged

3. The brake part was disassembled for inspection, and the internal parts were free of obvious wear and damage. After cleaning, it was reinstalled, and the fault remained the same

4. The working principle of the braking part (see Figure 1) is: when the machine is running, the electromagnet 4 is powered on, and the friction plate 2 is attracted, so that it is separated from the friction plate 1, and the parts will be loose. The motor spindle drives the friction plate 1 to rotate. When the machine stops running, the electromagnet 4 is powered off, and the friction plate 2 is pressed on the friction plate 1 under the action of 12 pressure springs 3, so that a sufficient braking friction force is generated between the two friction plates of chlorinated polyethylene rubber blended waterproof coiled material jc/t684 ⑴ 997

from the analysis of the fault phenomenon, the first time you press the operation button, it should be to start the alarm, and the machine does not run, but in fact, the machine runs slightly, which proves that it may be that the spring 3 is aging and the elasticity is reduced due to the long service time, so the friction between the two friction plates cannot meet the braking requirements, so the equipment starts the safety protection device, which leads to the normal operation of the machine

disassemble the braking part again, add a 1mm thick pad under each spring, and restart the machine after installation. The fault display signal disappears. After repeated startup for several times, the equipment can operate normally, but when it runs at low speed for about 20 minutes, the speed drops significantly, and the braking part smokes. Thus, it is judged that the fault is here

5. After basically identifying the cause of the fault, the brake part was disassembled again, and the 1mm thick pad under the spring was replaced with 0.5mm thick. After installation, it was checked that there was no abnormality after startup. Renewable resources and circular economy have become a social resonance. After several days of test run, they are normal, proving that the fault has been eliminated

it can be seen from the above that this method is very simple, only 12 0.5mm thick flat pads are needed, and replacing a set of braking device costs more than 40000 yuan

source: Printing Technology

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