Reason why the compressor auxiliary oil pump cannot start automatically when it stops
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When the centrifugal compressor is shut down, the auxiliary oil pump is set to start automatically; the lubricating oil used is 46# turbine oil, and the pump is a screw pump. However, the auxiliary oil pump trips due to a timeout when starting automatically, but it starts normally upon the second manual attempt. What are the common causes for this?
Is there a fault reset device?
Check if there’s a problem with the chain? Or could it be that after the compressor stops operating, the equipment becomes overloaded and loses power, preventing the auxiliary oil pump from starting?
One possible reason is that lubrication systems usually have a high-pressure interlock; the system will shut down when the outlet pressure exceeds 4.5 bar g. In winter, the ambient temperature is low; as a result, the temperature of the oil inside the pump also drops, its viscosity increases, and the outlet pressure rises (this is typical for gear pumps), leading to shutdown of the pump. When you start it for the first time, the liquid inside the pump is cold, so it shuts down. By the time you start it for the second time, the cold oil has already been pumped out (since there is usually a thermostatic heater in the fuel tank), and some of the cold oil has also been drained from the pipelines; as a result, the pressure at the pump outlet has decreased, allowing normal startup.
From an electrical analysis: Interlock switch failure； Moisture inside the switch affects the operation of the interlock switch.
Without a fault reset mechanism, the auxiliary oil pump will shut down after a timeout if the compressor stops operating suddenly!
It seems what was said on the 4th floor makes sense; now that the temperature has risen, if the problem no longer occurs, it must be related to the temperature!