Air compressor current issue
Thread Content
As shown in the figure, these are the experimental operation data of a certain air compressor: black represents the outlet pressure, the red line indicates the motor current, and blue represents the exhaust volume. At time 7.37, the motor current increased sharply, the outlet pressure dropped sharply, and the exhaust volume also decreased (it had been increasing gradually up to that point; why is this?) ). I would like to ask about the reasons for the sharp increase in motor current at that point, as well as the impact of the air compressor’s intake and exhaust valves on its operation. Additionally, I want to know where these intake and exhaust valves are installed – whether they are part of the compressor system or along the path from P04 to tank E1
A sudden drop in pressure causes an increase in inlet flow rate, leading to an increase in current. It is not known how specifically the pressure will decrease. The issues should be presented in a comprehensive and detailed manner.
For good schools, I would like to ask about intake and exhaust valves. When air flows out of the tank, is the outlet pressure determined by the settings of the exhaust valve? And when calculating the work done by the air compressor, how should the intake valve and exhaust valve be taken into account?
It seems to be a centrifugal compressor based on its capacity; I’m not sure what that means. What problem needs to be solved. Is it to solve problems or to do design – what needs to be calculated? It is recommended to draw a small flowchart to illustrate it.
It’s like this: this system is primarily used for collecting and monitoring data from the air separation process on-site. I would like to add functionality for monitoring failures in air compressors, as well as calculating their efficiency based on the information provided by sensors. The formula for efficiency is W=10^3*Q*Po*InP2/P0 (under the assumption of ideal isothermal conditions). I also want to implement something similar to an expert system to categorize and analyze various issues. However, I’m not very familiar with the working principles and operation of air compressors. I’m not sure whether the calculations using these data are correct, or whether it’s necessary to take into account the opening degree of the intake and exhaust valves, and what impact such opening degrees have on the operation of the air compressor.
1. For similar problems, it’s not sufficient to simply provide a trend curve; for example, the location of the measurement points needs to be specified, the process flow must be described, and information about the type of compressor is also required. 2. Taking a centrifugal compressor as an example, the outlet pressure of such a compressor is closely related not only to its own performance but also to the back pressure. When the compressor is operating normally, changes in back pressure or resistance in the outlet pipe will result in changes in the outlet pressure. 3. Based on the provided trend records, if the pressure decreases, this could be due to factors such as inlet throttling or a decrease in back pressure； The former reduces the flow rate, while the latter increases it. 4. If there is no other drive source besides the motor, an increase in current indicates an increased load on the motor; factors caused by the compressor may include an increase in flow rate and pressure. 5. The information provided by trends is very limited, making it difficult to draw conclusions
Thank you for the response. For centrifugal air compressors, during factory testing, the back pressure should remain constant; the opening degrees of the intake and exhaust valves remain roughly unchanged around the moment when the motor starts to vibrate. However, the air temperatures before and after the pre-cooler increase (the pre-cooler is connected between the air compressor system and the tank). Afterwards, the system’s exhaust pressure returns to its normal level, the exhaust volume increases, the temperatures before and after the pre-cooler rise, and the current consumption increases as well. (Pictures cannot be inserted. . . ) What causes the sudden increase in motor current? Is it caused by an increase in temperature? ), could you introduce the process of change?
1. The process is not very clear – is the pre-cooler located at the outlet or the inlet of the compressor? 2. If the inlet temperature of the compressor rises, the gas volume flow rate increases, the motor power goes up, while the flow rate indicated by the curve decreases. 3. If the pre-cooler is located at the compressor outlet, since the gas temperature rises after compression, cooling this gas results in a decrease in the volume flow rate downstream of the compressor; this leads to a reduction in pipe resistance and back pressure, which in turn affects the pressure at the compressor outlet. 4. The introduction states that both the inlet and outlet temperatures of the pre-cooler have increased, indicating that there are other influencing factors outside the pre-cooler. 5. The temperature of the medium has an impact on the system