How to detect failures of  air compressor motor

1.Some common failure of 3 phase asyncronous motor.  

1.1 Motor is quickly overheated, groaning and   unable to start when connect to power supply ( slowly spin or not spin).
- Causes :
+Power supply  loses 1 phase
+ Inner phase of stator is broken 
+ Bearing is worn out so  rotor is clogged 
- Remedies 
+ Check and repair  power supply wiring, fuses, contactor, main switch
+Measure and check each phase and repair brokren position. 
+ Check the loose of bearing. Repair or replace bearing 
1.2The protective equipments are reacted immediately after power connection
- Cause 
+ Stator is short- circuited
- Remedies :
+ Check and repair the dhort-circuited phase. 
1.3 Engine runs with insuffcient speed, strong vibration, quickly -overheated.  
- Causes 
+  Short circuit in Inner coil  
+ The engine is destroyed
- Remedies:
+ Check wirings by Gronha , if it is internaly short-circuited , wrap it. 
+ Recalibrate or replace new bearing .
1.4 Mechanical sound, current is abnomal increase.
- Causes 
+ The cap is not well-fixed to the machine
+Bearing is worn out, shaft is curvied.
- Remedies :
+ Repair and correct mechanical parts.
+ Replace bearing 
1.5 Engine runs with sufficient speed but 3 phase electric current is unbalanced (deviation more than 10% in each phase)
-Causes 
+ Short circuited phases 
- Remesies:
+ Check source voltage  điện áp nguồn
+ Check short-circuited position.
1.6 The load current is not too high Io> 50% Iđm
- Cause 
+ Poor quality circuit
+ Many winding is shorted-circuit 
- Remedies 
+ Enhance drying. If there is a change, it can be useD, If not it  must be corrected
1.7 Engine can not start while loading 
- Causes 
+ Heavy load 
+ Decrease sourse voltage 
+ Phase loss
- Remedies 
+ Decrease load 
+ Check the sourse voltage 
+ Check power supply

Other article: Six tips to  repair 1-phase asynchronous electric motor, How to read the parameters of bearings, 10 things to know when using bearings,