Alup screw compressor overload tripping

Hi, Overload tripping usually is one of two things: - Problem with compressor element - Problem with electrical system You can check the first by trying to rotate the compressor by hand (make sure the compressor is completely shut down and the power is turned off!). If that is easily possible, and there are no 'high points', than it usually is OK. The second option is an electrical problem. This could be in your frequency drive (converter) or in the electric motor. Easiest to check is the electric motor, but you will need a special tool for this: an isolation tester (high-voltage resistance meter). Check the isolation resistance of the motor between the three phases and between the phases and ground. it should be in the mega-ohms. Also, check with a normal multi-meter is all the motor windings are ok. It should be somewhere about 50-10 ohms. Good luck and let me know if you need more info.