The motor current of the reciprocating compressor is too high
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The motor current of the reciprocating compressor used in our company is too high. We have already checked the crankshaft couplings, bearings, as well as the air supply system. Additional information: The current exceeds the normal level once pressure is applied, to the point that several AC contactors have been damaged. Please help analyze this issue; thank you
Was it checked whether the inlet and outlet valves were inspected for the gas circuit? Please provide a detailed description of the operating conditions before and after the excessive current occurred – whether it was functioning normally beforehand, or if problems were already detected during the testing phase.
If everything else checks out fine, check whether the process conditions have changed and whether there are any issues with the opening degree of the inlet and outlet valves: handshake
It was working fine before. The problem started recently; the inlet and outlet filters have been checked and replaced. I’m not sure what impact the inlet and outlet valves might have on it
Have the process parameters changed? Has the outlet pressure changed? Entrance and exit valves generally have no impact.
First, check whether there is any change in the inlet and outlet pressures. When the inlet pressure increases, the load on the machine rises; if the inlet pressure remains normal but the outlet pressure increases, the machine’s load also increases； One question is: whether the pressure gauge is located in front of or behind the inlet and outlet valves, and whether the pressure reading cannot reflect the actual gas flow rate when there is a problem with the valves ； If there are any changes in the gas composition, and the proportion of large molecules increases, the load will also increase
I agree with the analysis above; if it is a mixed gas composition, excessive levels of the heavier components can cause the compressor to become overloaded. Additionally, an excessive outlet pressure can also lead to compressor overload.
It is likely that the load rating of the motor was chosen too low. Our unit is equipped with a pump; when the flow rate at the outlet is a bit high, the motor experiences overcurrent and eventually burns out. We replaced it with a larger motor, and the result was much better. I guess the same principle applies to compressors as well.
Apart from the reasons mentioned by the above, it’s also because the motor selected is too small – using a weak engine to drive a heavy load
In addition to checking the manufacturing process, it is also necessary to verify whether the clearance between the friction pairs has been set according to the technical specifications, as well as whether the oil and water circuits and interlocks are functioning properly. This is a delicate task. Furthermore, it is important to ensure that the process media and motor selection are appropriate
It might be that the gas composition from the previous section has changed, resulting in an increase in gas density. Has the intake air temperature changed, and are the cooling systems at each stage functioning properly? Are there any problems with the electrical system?