# Air compressor start error



## Hieu153 (1 mo ago)

I have an air compressor with below spec:

model : r160i_a8.5
mnf. : ingersoll
rated press. : 0.75 mpa
rated power: 160 kw
i use mc500 soft starter for air compressor motor.
Currently, i difficulty start an air compressor. when i press start, a screen displays alarm:

low sum air pressure : this alarm appears if the pressure drops 1.4 bar.
check motor rotation
and when to appear this alarm, the air compressor can not start. But sometimes i can start the air compressor without alarm.
When starting the air compressor, i dont see a current of the motor in soft starter.
Especialy, sometime i can start a motor by manual on soft starter. After, i change to auto and air compressor can operating.
Please tell me what cause of this problem!
Thank you.


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## StevenHill (Feb 21, 2018)

There might be a switch on the intake valve at the air filter, the switch looks for pressure/vacuum when you start the compressor if the switch does not make then it tells the controller the compressor is going the wrong direction 
you can usually link this switch get the compressor running


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