JLS205 (or 206) type offset printing machine may sometimes fail to increase the maximum speed during operation. Among its many reasons (1. The circuit lacks phase or undervoltage operation; 2. The corresponding normally open contact of the increasing and decelerating relays is badly closed; 3. The control circuit voltage output is insufficient ...), the top number is six in the main circuit The most difficult to repair is the output current of the thyristor is inconsistent (the difference between large and small is quite large). This is because: to repair this kind of fault, it is usually necessary to use a double-track oscilloscope to readjust the trigger angle of its six triggers to make them return to the same-the output current values ​​of the six thyristors in the main circuit also return to the same Only then can the fault be eliminated. However, the adjustment with a dual-track oscilloscope has many operating procedures and is time-consuming, especially at night or when the production task is very tight. Even more annoying or useless. In order to solve this problem, I developed a method to measure the AC input current value of each thyristor with a clamp ammeter instead of using a dual-track oscilloscope to measure the trigger angle of each trigger (actually, it is indirectly measured by measuring the current of each thyristor The trigger angle of each trigger) is simple and practical, and can basically achieve the purpose of quickly troubleshooting (and there is no possibility of problems in the use of clamp-type ammeters). The details are as follows (this method requires two people to cooperate in maintenance):
After opening the front and rear doors of the power distribution cabinet, run at low speed, and then increase the speed to medium speed. A person at the back door of the power distribution cabinet, holding a clamp-type ammeter, respectively measured the AC input current value of the six thyristors in the main circuit ), And make corresponding records, and then tell the person standing on the front door side to adjust the trigger angle of the six triggers for easy adjustment (the person who stands on the front door side should maintain the six triggers on the “slope†in advance) The lock nut of the potentiometer is loosened so that it can be adjusted with an electric pen. The installation position of the six triggers on the front door side of the power distribution cabinet is shown in Figure 2.)
According to the measured current, the minimum and maximum should be selected first and adjusted first. Because the current of one thyristor (because of adjustment) changes in the three-phase full-controlled rectifier circuit, it will cause a chain reaction of the current of the entire circuit-the working current that affects another or several thyristors also occurs Change, and the greater the current change of the person being adjusted, the greater the current impact on the other thyristor or other thyristors. Therefore, when adjusting the "slope" potentiometer, fine adjustment should be appropriate, and it should not be too large; otherwise , It is possible to make the circuit more and more chaotic.
For example, if the output current of No. 1 SCR (SCR1) is 2A and the output current of No. 6 SCR (SCR6) is 18A, the output current of other thyristors is measured at About 9A, it means that the current reference value of the entire circuit should be about 9A; you can use 9A as the reference value to fine-tune the "slope" potentiometer of No. 1 trigger to gradually increase its output value-the output of No. 1 SCR The current is gradually increased from 2A (for example, it is increased to 6-7A), and then the output current of SCR 6 has also been reduced by 18A (for example, it has been reduced to 13-14A)? If there are changes, it means that the adjustment is effective, then continue to fine-tune No. 1 trigger, so that the output current of No. 1 SCR continues to rise, and the output current of No. 6 SCR follows the decline until they reach the ideal value of 9A (also can be reversed) Come over and fine-tune the "slope" potentiometer of No. 6 flip-flop to make the output value of No. 6 flip-flop smaller-the output current of No. 6 SCR drops, and at the same time force the output current of No. 1 SCR to rise until the average Reach the ideal value of 9A); or alternately adjust two (No. 1 and No. 6) flip-flops (this is to adjust a trigger to change the current of the thyristor, but it cannot make the current of the other thyristor also occur) The reverse change of the same proportion, or both sides can not reach the normal value after the change, but there are some differences, then you need to use alternating and coordinated adjustment methods to make the effect), so that the output current of the thyristor controlled Gradually converge.
Then measure the working current of several other thyristors-see if there is any increase or decrease in current caused by the adjustment? If so, adjust them separately according to the situation ... When the working current of the six thyristors is adjusted to be consistent (normal value), the speed will be increased synchronously; then press "Increase speed" again To make the machine speed as high as possible-to see if it can reach the highest speed? If the highest speed can be reached, it means that the adjustment is successful once; if the highest speed cannot be reached, the AC input current value of the six thyristors at high speed can be measured separately with a clamp ammeter, and the one with the larger difference is selected. Fine adjustments are made until the output currents of the six thyristors tend to be the same-the machine speed can rise to the highest speed. Then press deceleration to reduce the speed to low speed and then shut down. In order to detect whether the fault has been completely eliminated, you can turn it on again (including jog, low-speed operation, increase and decrease) and try again. After no error, re-tighten the lock nut of the "slope" potentiometer on each trigger.
Spring and Autumn Horse Rug is windproof or waterproof with lightweight or without padding thickness.
Spring And Autumn Horse Rug,White Polycotton Horse Rug,Polar Fleece Horse Rugs,Summer Horse Rugs
Hebei Honde Group , https://www.horseequipmentfromchina.com