Check the isolation of the motor windings. Should be in the mage-ohms (you need an isolation tester / high voltage ohm meter for this). Check the voltage when the compressor is running. If the voltage drop significantly when the compressor starts/runs, you have a bad connection somewhere.
[pdf] The checklist combines the applicable requirements of 29 CFR 1910, American National Standards Institute (ANSI) Standards, American Petroleum Institute Recommended Practice 54 (API RP54), other more specific American Petroleum Institute Recommended Practices, and the current and previous checklists for drilling and well servicing rigs generated by the International Association of Drilling Contractors (IADC) and the Association of Energy Service Companies (AESC).
[pdf] Sullair is the world's largest manufacturer of rotary screw air compressors. It was founded in 1965 and headquartered in Michigan City, Indiana, USA. As a pioneer in the compressor field, Sullair's manufa.
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