Check for correct oil level at the ll plug location on the compressor. The oil level is full when oil is at the bottom of the threads in the ll plug hole. Check for oil purging from the air dryer. Refer to the image below as an example.
[pdf] Rotor clearance issues or debris can lead to metallic contact sounds Loose or worn belts squeal or howl, especially under load Airflow pulsations, valve leaks, or turbulence create hissing or whistling Bolts, nuts, and mounting pads loosen over time, amplifying noise
[pdf] When matching motor characteristics to compressor requirements, one should consider factors such as voltage, phase, and duty cycle. The motor’s rated horsepower should ideally be closely matched to the compressor’s demands to ensure optimal performance.
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