Fault phenomenon:
The folding machine suddenly stops during normal use, and the touch screen shows nothing. The operator immediately shuts off the power and informs the maintenance personnel. Because the motor does not move, first check the power input, 380V normal, the transformer output is also normal. In accordance with the circuit diagram from the power to start, 380V power supply voltage through the transformer, the output of two voltage: one is 24V, the supply relay coil; all the way to 220V, supply switching power supply, the main motor, paper table motor in the course of the operation has no smell and abnormal sound This shows that the main motor and paper table motor are normal. Since the time taken by the folding machine is not long, it is unlikely that the Mitsubishi general-purpose inverters FR-E540-2.2K-CHT and FR-E540-0.75K-CHT that control the main motor and paper table motor will have problems. This starts with the relevant control part. The control center of the folding machine is Mitsubishi PLC. As shown in Figure 1, the model is FX2N-48MT. It is connected to the man-machine interface F930GOT-BWD-C, and two general-purpose inverters are controlled by the PLC. To control two motors. This PLC is an AC power supply DC input, input 24 points, output 24 points, transistor output, from the power supply + CPU + input and output + program memory (RAM) unit type programmable controller.
First, carefully observe the PLC on the right side of the action indicator, power indicator, running indicator, all normal, and program error indicator no flash, CPU error indicator did not light, indicating that the PLC itself is no problem. However, the PLC input indicators are not displayed, press the jog button on the console, and it is found that the PLC's corresponding input indicator does not respond. Press the paper table up/down button and the PLC's relative input indicator will not respond. At this moment, the author suddenly thought that the touch screen of the man-machine interface is all black, and it should be powered by DC24V. All black indicates that it has no DC voltage supply, and the PLC, as a DC input, should be DC 24V, and 24V input is not measured by a multimeter. Referring to the circuit diagram, it shows that the switching power supply has no output. Using a meter, it is true, but there is 220V input. Combined with switching power supply principle: power supply first high-voltage alternating current (220V) through a full-bridge diode rectifier after a high-voltage fluctuations in DC, and then through the capacitor filter becomes a relatively smooth high-voltage DC. At this time, the control circuit controls the high-power switch to send the high-voltage direct current to the primary of the high-frequency transformer in batches according to a certain high-frequency frequency, and then converts the stepped-down high-frequency low-voltage alternating current output from the secondary coil into a high-frequency transformer, which is converted into a rectified filter. Low-voltage, high-current direct current. Cut off the input power to the device and remove the switch power supply for the insurance measurement without blowing. Look closely at the components of the switching power supply circuit board. No components are found to burn or break down. If the above test results are normal, then the four rectifier diodes of the power supply are detected. In the normal state, the forward resistance of the diode is several k (tested with a multimeter x 1k block), and the reverse resistance is close to infinity. Found that the test results are normal. After checking down, the next thing to do is to test the DC resistance of the power supply. The normal resistance is also a few k and the measurement is normal.
Excluding the above-mentioned problems of switching power supply, it shows that most of the faults exist in the oscillation control circuit, sampling feedback circuit or load. In this case, check the power supply circuit of the oscillating manifold. The normal voltage should be around 10V. (Special reminder: Since the test voltage should be conducted under power, the power board has high voltage, so pay special attention to personal safety Do not try to touch any part of the power supply directly.) Measured with a multimeter, the meter display is normal, the oscillating manifold and its external power supply circuit are all normal, and finally we can only replace with a normal switching power supply, and the fault persists. However, when the load is disconnected and the output is normal, the author suddenly thinks that the power supply cannot output the voltage normally. It may also be caused by a load short circuit causing the power supply protection. Since there is no problem with the switching power supply itself, check the switching power supply according to the circuit diagram. The peripheral power supply modules were checked one by one. When the folding counter was checked, it was inadvertently found that the end of the steel wire that was wrapped around the signal wire and was close to the counter entered the signal line, causing a short circuit in the input wire. The model number of the counter is HPJ-A21, which is a photoelectric switch with built-in amplifier type and infrared diffuse reflection type. The output state is NPN open collector.
When there is paper passing, the tube is turned on, and a high voltage is output to the PLC signal to count. When the input voltage is short-circuited, the switching power supply short-circuit protection circuit operates so that it has no DC output.
The company's YJB8-50 disc packer used this machine. When the book block suddenly passed during use, as long as the machine is running, the air pump is turned on, and it will stop on the cover. I suspect there is a problem with the reflective photoelectric switch. Its model is E3JK. -R4M1, the principle is shown in Figure 3: Use a white paper to detect, the corresponding output voltage, no problem. There is no change in the position of the cam block controlling the upper cover, and there is no conflict between the movement timing of the suction nozzle on the upper cover and the movement of the tray. Remove the solenoid valve and find that the closing position of the solenoid-controlled closing element is not on the base of the cover and it is already skewed. Severe corrosion, take out sandpaper clean, reset, power equipment is operating normally.
In the process of repairing the equipment, I took a lot of detours, but this led the writer to understand that the current printing equipment is mostly machine, light, and electricity. The demand for operators and maintenance personnel is getting higher and higher, and only continuous learning is required. With profound theoretical basis and rich practical experience, we can keep up with technological progress.
A training chair is a seat designed specifically for activities such as training and meetings. It has the characteristics of comfort, durability, and ease of movement, which can meet the needs of different groups of people. Training chairs can be classified into various categories based on material, structure, function, and other aspects. Below will be a brief introduction to the classification of training chairs.
1. Material classification
The materials of the training chair mainly include metal, plastic, and fabric. Metal training chairs typically have strong stability and durability, making them suitable for long-term meetings or training activities. The training chair made of plastic material has the characteristics of lightweight and easy to clean, making it easy to arrange the meeting site at any time and suitable for use in multifunctional halls and other places. The training chair made of fabric has a comfortable sitting experience and good breathability, making it suitable for long-term meetings or training activities.
2. Structural classification
The structure of training chairs mainly includes single chairs, linked chairs, and foldable chairs. Single chairs are the most common training chairs, with each seat being independent and adjustable as needed. Chainage refers to the connection of multiple seats together, usually in the form of one or more rows, suitable for use in large training venues. Stackable chairs are training chairs that can be folded and stacked, saving space and facilitating storage and handling.
3. Functional classification
The main functions of the training chair are adjustable, rotatable, foldable, and storable. The adjustable training chair can adjust the height and angle according to personal needs, providing a more comfortable sitting posture. The rotatable training chair can rotate 360 degrees, facilitating communication and interaction with people around it. The foldable training chair can be conveniently stored and transported, making it suitable for use in multifunctional halls and other places. The training chair that can store items is designed with storage space below or behind the chair, making it convenient to store items such as stationery and documents.
In summary, the classification of training chairs mainly includes material classification, structural classification, functional classification, etc. Choosing a suitable training chair can provide a better user experience and improve the effectiveness of training and meetings.
Meeting Chair,,Foldable Chair,Customized Chair
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