According to the structure and working principle of the machine, it can be seen that the machine is mainly composed of a base, a pressure frame, a high-power bidirectional electromagnetic clutch transmission mechanism, electrical control, and other parts. The action of pressing and cutting paper products is achieved by the electric motor installed on the right side of the machine base, driving the transmission shaft through the flywheel, and driving the press frame to reciprocating motion through the secondary gear transmission link. If the ribs between the splines and grooves on the electromagnetic clutch experience severe wear during operation, resulting in a reduction in the width of the ribs and a very loose fit between the splines and grooves, then during the clutch action, the spline copper sleeve will deviate from the axial clutch action of the splines and become stuck, preventing normal axial clutch sliding. At this moment of being stuck, Often, the rectifier is damaged (or some of the circuit's fuses are blown), causing the electromagnetic coil of the clutch to have no current and preventing the clutch from acting.
Based on the above analysis (similar situations have also occurred in the past), we removed the friction wheel and inspected the spline copper sleeve. The results showed that there was a lot of wear in the width direction of the spline sleeve rib, and the fit was very loose. At the same time, the clutch compression spring uniformly distributed in the four holes on the friction wheel surface has fatigued and broken, and the friction plate on the friction wheel has also worn to its limit and needs to be replaced.
Based on the above situation, the spline copper sleeve and the four compression springs of the clutch were replaced, and new friction plates were also installed. Subsequently, the machine was turned on for a trial run, and only one cycle was activated. The fuse of the rectifier circuit (code: FU3) then melted again. At first, we thought it was due to the poor quality of the fuse, so we increased the capacity of the fuse appropriately before starting the test. However, after only one cycle of operation, the fuse burned out again.
Where exactly is the problem? Through in-depth analysis of the wire cutting machine, we believe that the recurrence of such a malfunction after replacing the aforementioned parts should be attributed to an electrical fault. So a detailed inspection was conducted on the control circuit of the electromagnetic clutch. Firstly, use a multimeter to measure the DC resistance of the electromagnetic coil of the clutch, and then compare the DC resistance value of the electromagnetic coil on another machine that is operating normally. It was found that the DC resistance value of the electromagnetic coil on the clutch of the faulty machine is significantly lower than the normal value. This indicates that the fault is caused by the electromagnetic coil and its circuit. There are several main reasons for the analysis:
1、 Short circuit between turns of electromagnetic coil;
2、 Poor insulation of electromagnetic coil to ground;
3、 Short circuit or poor insulation between the slip ring and the spindle.
We will separate the wiring of the electromagnetic coil and the slip ring, and first measure the DC resistance of the electromagnetic coil separately. The result is that its DC resistance value is the same as the normal value. The magnetic force generated when the solenoid coil avoids the slip ring (also known as the Slip ring) and is directly energized is also normal. On site, through these two tests, it can be considered that the electromagnetic coil is normal. So, the resistance of the slip ring to ground insulation (i.e. the insulation between the slip ring and the spindle) was measured, and the result was that the resistance value was close to zero. This indicates that there is a short circuit between the slip ring and the spindle, and the slip ring must be removed for inspection and handling.
The insulation and assembly between the slip ring and the spindle are as follows: using insulating adhesive