Paper cutter electrical repair

When we used the 115MCS-2 paper cutting machine imported from Germany, the paper cutter sometimes appeared and sometimes did not come down. After the platen is compacted, press the two-handed button to cut the knife at intervals. After pressing the cutting button repeatedly, there is no need to cut the knife at all, nor can it be used manually.

First of all, we start the analysis from the drawing and look for the cause of the failure. Find the part of the line under the control of the knife, the fault is basically located in the electrical part of the relevant components due to false contact. Look at the master knife clutch on the drawing, press the two-hand cutting button, contactor K50, K51 has been sucked, normally open contact K50, K51 closed. Look again at the solenoid valve Y1, which is located inside the machine's left door large transmission wheel. Through careful observation, it was found that when the crankshaft sparked, the spring of the solenoid valve Y1 could not rebound, resulting in false contact between the carbon brush and the wheel. Causes the motor circuit to be unable to connect, the electrical machinery cannot turn up, also cannot cut.

Since this paper cutter has been used for many years, long-term operation deteriorates the spring recovery performance. Fortunately, when the manufacturer designs the spring, it has 3 adjustable positions. By adjusting the spring position, the fault can be smoothly eliminated.

Through this failure, combined with similar failures that I encountered at ordinary times, I came to the conclusion that, in the face of such problems, it should be first considered whether or not the electrical components are not in contact. Unreal contact is mainly due to false contact, improper contact of terminals, and improper solenoid valve pull-in. However, specific problems must be analyzed.