Purification Technology Edition: Daily Question [2018-1-23]
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Power supply failure, how to handle it? 1. Immediately close the main clean gas outlet valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
Power supply failure, how to handle it? Answer: 1. Immediately close the main outlet gas valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
Answer: 1. Immediately close the main outlet gas valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
1. Immediately close the main clean gas outlet valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
1. Immediately close the main clean gas outlet valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
1. Immediately close the main clean gas outlet valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
Answer: 1. Immediately close the main outlet gas valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
1. Immediately close the main clean gas outlet valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.
Common faults and repair methods for switch-mode power supplies: 1. Blown or fried fuse. Check mainly the large filter capacitor at 300V, each diode in the rectifier bridge, as well as the switching transistors; problems with the interference suppression circuit can also cause the fuse to blow and turn black. It should be noted that when a fuse blows due to the breakdown of a switching transistor, it usually damages the current sensing resistor as well as the power control chip. Negative temperature coefficient thermistors can also easily be damaged along with fuses. 2. No output, the fuse is intact. This phenomenon indicates that the switching power supply is not working or has entered protection mode. First, it is necessary to measure whether there is a start voltage at the start pin of the power control chip. If no start voltage is present or the voltage is too low, then it is required to check whether the start resistor and the components connected to the start pin are leaking current. If the power control chip is functioning properly, the fault can be identified quickly through these checks. If there is a startup voltage, then check whether there is a transition between high and low levels at the output terminal of the control chip at the moment it starts up. If no such transition occurs, it indicates that the control chip is faulty, or there are problems with the components of the external oscillation circuit or the protection circuit. In such cases, it is advisable to replace the control chip first and then examine the external components. If a transition does occur, it is usually due to a malfunction or damage in the switching transistor. 3. There is an output voltage, but it is too high. This type of fault generally originates from the voltage regulation sampling and voltage regulation control circuits. The DC output, sampling resistors, error sampling amplifiers such as the TL431, optocouplers, and power control chips together form a closed control loop; any issue in any of these components can lead to an increase in the output voltage. 4. Low output voltage. In addition to the voltage regulation control circuit, several other factors can also cause a low output voltage: a. There is a short-circuit fault in the load of the switching power supply (especially a short circuit or poor performance of the DC/DC converter). In such cases, it is necessary to disconnect all loads connected to the switching power supply circuit in order to determine whether the fault lies with the switching power supply circuit itself or with the load circuit. If the voltage output at the load circuit is normal when the load is disconnected, it indicates that the load is too heavy; if it remains abnormal, then there is a fault in the switching power supply circuit. b. Failures such as defective rectifier diodes at the output voltage terminal or filtering capacitors can be diagnosed using the substitution method. c. A decline in the performance of the switching transistor inevitably results in its inability to conduct properly, which increases the internal resistance of the power supply and reduces its capacity to drive loads. d. A faulty switching transformer not only causes a drop in the output voltage but also leads to insufficient excitation of the switching transistor, resulting in repeated damage to it. e. A faulty 300V filter capacitor results in poor load-carrying capacity of the power supply; the output voltage drops as soon as a load is connected.
Answer: 1. Immediately close the main outlet gas valve on site. 2. Manually close the large rough gas valve. 3. Stop spraying methanol. 4. Manually close all level and flow control valves. 5. Stop the pump and the circulation system, close the high and low pressure shut-off valves, and proceed with the subsequent shutdown procedures.