Either an electrical problem, or the compressor has tripped on a safety device. Check supply power. Check for errors on display. Check emergency stop is out. Check and reset the overload relay. If it’s a new installation, check the phase sequence. Ambient temperature too high or not enough ventilation.
[pdf] One of the most common ways to check if your air compressor tank is leaking air is to hear it closely. Try implementing a system in which someone will walk close to the tank and search for any hissing nois.
[pdf] Heat generated during compression can cause air expansion before intake is completed. Poor cooling performance—whether due to inefficient oil cooling or water cooling —raises internal temperatures and reduces overall intake volume. Air displacement is directly proportional to rotor speed.
[pdf] 
