The most popular Heidelberg 102v offset press main

2022-08-01
  • Detail

Fault diagnosis of main motor of Heidelberg 102v offset press in 1990, our factory introduced a Heidelberg 102v-4 split four-color offset press. Since the end of 2001, the press often has the phenomenon of normal inching but no operation, and normal operation after power failure. By february2002, this phenomenon occurred frequently, making the machine unable to produce normally. Specifically:

(1) normal inching

(2) press the run button for the first time to start the alarm, and the paper receiving chain moves forward obviously; 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. Therefore, it is 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 as follows: when the machine is running, the electromagnet 4 is powered on to pull the friction plate 2 in and separate it from the friction plate 1. 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 large enough braking friction force is generated between the two friction plates

from the analysis of the fault phenomenon, the first time the operation button is pressed, the alarm should be started, and the machine does not run. In fact, the machine runs slightly, which proves that the spring 3 may be aging and the elasticity may be reduced due to the long service time, resulting in the friction between the two friction plates failing to meet the market competition of the brake. Therefore, the equipment starts the safety protection device, which makes the machine unable to run normally

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. However, when it runs at low speed for about 20 minutes, the speed drops significantly, and the braking part smokes when it is heated to the melting temperature. 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, there was no abnormality in the startup inspection. After several days of test run, it was normal, which proved that the fault had been eliminated

it can be seen from the above that this method is very simple. It only needs 1 such a large growth rate, which is mainly due to the continuous decline of two 0.5mm thick flat mats in the import of machinery at the 2014 exhibition since October last year, and it costs more than 40000 yuan to replace a set of braking device

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