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] This manual describes the safety precautions, structure and functions of all systems and components, as well as the operation and maintenance methods for the KHE series rotary screw air compressors. The owner and operator shall read the manual carefully.
[pdf] Each screw machine must be equipped with a gas storage tank and, if needed, auxiliary equipment such as a cold dryer and a filter. The installation requirements are as follows: A) The installation sequence of supporting equipment is: “air compressor → gas tank → gas-water separator → cold dryer.”
[pdf] 
