Starting a reciprocating compressor after a sudden shutdown
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The power supply for my device is not reliable; there are frequent power outages. Either it’s due to lightning, which causes the device to stop working temporarily before power is restored immediately, or it takes about ten minutes for power to be restored again. After a sudden stop, if the operator is on site, we usually immediately press the start button to restart it ； If a call is expected after some time, the inlet and outlet valves will be closed, and startup will take place without load once the pressure is released. Personally, I think pressing the start button right after a lightning strike is somewhat like using a brute-force approach; starting the motor under load results in high stress on the motor (since there is no variable frequency control), and the shaft torque also increases significantly. I wonder how those more experienced folks handle it? Or is there something wrong with the way we are operating? Thank you for your active discussions
Large compressors should be started at zero load. Otherwise, the instantaneous load will be too high, which can burn out the motor.
Reciprocating compressors must never be started under load; therefore, in the event of a sudden shutdown due to lightning, it is necessary to release pressure first and then proceed with the startup procedures for the unit.
It was indeed a brutal approach. The current during startup under load is excessively high, which can burn out the motor – a situation that is not worth it.
Moreover, the motor does not have variable-frequency starting; every time it starts, the current immediately reaches its maximum value of 500A, which is quite worrying
I’m not sure if the unit has an automatic backflow valve; if it does, this could help reduce the starting load and minimize damage to the electrical components. I hope everyone will participate in the discussion.
Reciprocating compressors must never be started under load; the motor has to exert more than twice the normal working power during startup. After an unexpected shutdown, the compressor must be depressurized before it can be started again under no-load conditions.
Start the standby machine\ud83d\ude05
Reciprocating compressors must not be started under load; you can start the backup compressor and then relieve the pressure from this compressor
First, reciprocating compressors generally start with zero pressure and zero load. However, there are exceptions: if the inlet pressure is relatively low, it is possible to ask the manufacturer to recalculate the starting torque of the motor and confirm with them whether the motor can start; in this case, the return line is also fully open, or the check valve is fully opened as well. Secondly, if, at the initial stage of equipment selection, the manufacturer is asked to determine whether the system will operate under pressure (at inlet pressure or below it) with zero load (with the return valve fully open or the pressure relief valve fully open), then a larger motor is selected; this is also a possible scenario.
Reciprocating compressors must never be started under load; therefore, in the event of a sudden shutdown due to lightning, it is necessary to relieve pressure first and then proceed with the startup procedures for the unit