6 tips to repair  the 1 phase asynchronous electric motor : 1 phase asynchronous electric motor is widely  applied in daily life such as : washing machine, bumping, grinding mạchine, fans drilling...
Low capacity  air compressor uses 1 phase asynchronous electric motor such as; air compressor used  to pump bicycles, dry motobike after washing...So the repair and maintenace needs is popular. In this article, some symptoms, causes, and remedies of 1 phase asynchronous electric motor which is booted by capacitor are introduced to you. 

1.  1 phase motor is slowly running, has  groaning sound and high current.
- Cause  : 
+ Tighten shaft
+ Inner short-circuited in some windings
- Remedies : 
+ Twist the cap, recalibrate rotor, check bearing or replace bearing. 
+ Check windings by gronha, if it is internally short- circuited , wrap it. 
 2. Only use motor crank  can start the engine .
- Causes :
+ Leakage of  capacitor makes parameters changed  
+ unbalanced calibration
- Remedies : 
+ Replace capacitor 
+ recalibrate
 3. Abnormal noise after power connection.
- Cause :
+ the bearings are pitted
+Bearing is worn out causing mechanical collision. 
- Rememedies :
+ Replace bearing
 4. The  capacitor is frequently broken when rewinding the stator 
- Cause:
+ Wrong the number of windings( decreasing the number of rings) causes voltage on the capacitor is bigger than that rated voltage.
+ Replace capacitors with smaller capacitance so the voltage on the capacitor is larger than the rated voltage of the capacitor
- Remedies :
+ wrap it
+ Replace capacitor 
5. Metal collision
- Cause 
+ If insulation between winding and  steel core is broken, wrap another new winding. 
+ Check and repair connector which  tough to the cover.
- Remedies 
+ If the inssulation is broken, changing new winding is nescessary
+ Check and repair connector which  tough to the cover.
6. Motor can not start after power connection, rotor is deflect, excessive vibration.  
- Cause :
+ Bearing  is worn out Do vòng bi hoặc bạc quá dơ
+ Te cap is deflected, rotor is inconcentric.
- Remedies:
+ Replace bearing
+ Twist the cap and recalibrate rotor 
Some notes:
- In order to ensure the motor  safety and durity, you should peridically maintain, leave motor in dry airy place. 
- Wraping moto, some notes should be paid attention to : wiring quality, number of rings, conductor cross-section ...to avoid loss motor productivity. 
- when detect some symptoms , disconnect the power supply, then using ammeter checks wirings if it tough the cover or not? Depending on the actual situation and specific conditions, you can use other measures (electric tester ...) to check but make sure that it's safe 
Other artical: How to detect failures of air compressor? some special cases of 3 phase asynchronous , see more