Failure | Cause of failure | Troubleshooting |
1. The electric motor doesn't rotate after being electrified. But there is no abnormal sound, peculiar smell and smoke. | ① No electricity (at least two phase); ② Fuse failure (at least two phase); ③ The debugging of the servo motor is not completed; ④ Wiring error of the control unit. | ① Check and repair the break point at the rotary switch of the power supply, fuse and junction box; ② Check the type of fuse, and the reason of fuse failure; change a new fuse; ③ Adjust the matching of the actuator and electric motor, adjust the parameters of the actuator; ④ Correct the wiring. |
2. The electric motor doesn't rotate after being electrified. And there is drone of the engine. | ① The power of one phase is cut off or failed; ② The terminal of winding outgoing line is connected in a wrong way or the internal of winding is reversely connected; ③ The contact of supply circuit is loose, so that the contact resistance is big; ④ The load of the electric motor is too big; or the rotor is stuck; ⑤ The supply voltage is too low; ⑥ The assembly of small electric motor is too tight; or the lubricating oil in the bearing is too hard; ⑦ The bearing is stuck. | ① Check and repair the break point; ② Check the polarity of the winding; ③ judge that if the winding terminal is correct; ④ Tighten the loose connection screws; check and repair the misconnection of the terminals of the winding by using multi-meter; ⑤ Load shedding or checking and removing the mechanical failure; ⑥ Check and correct misconnection; and if the power supply wire is too thin thus causing too large pressure drop; ⑦ Reassemble the electric motor and change the lubricating oil of the bearing; ⑧ Repair the bearing. |
3. It is difficult to start up the electric motor. The speed of the electric motor is significantly lower than the rated speed when the motor is running with rated load. | ① The supply voltage is too low; ② The connection of the electric motor is wrong; ③ Open welding or crack of the rotor; ④ Part of the coil of stator is misconnected or reversely connected; ⑤ The number of windings added during the repairment of the motor winding is too much; ⑥ The motor is overloaded. | ① Measure the supply voltage and then improve the condition; ② Correct the connection; ③ Check and repair the open welding and breaking point; ④ Check and correct the misconnection; ⑤ Restore the correct number of windings; ⑥ Load shedding. |
4. There is no-load current unbalance of the electric motor. There is big difference among three phases. | ① Misconnection of two ends of the winding; ② Supply voltage unbalance; ② Turn-to-turn short circuit, reverse connection of coil and some other winding failure. | ① Check and correct the connection of two ends of the winding; ② Measure the supply voltage, and try to eliminate unbalance; ③ Eliminate winding failure. |
5. The running sound of the electric motor is abnormal. | ① Beating abrasion or sand or impurities in the lubricating oil; ② The bearing is lack of lubricating oil; ③ Too high supply voltage or supply voltage unbalance. | ① Change or clean the bearing; ② Check and repair the iron core of the rotor; ③ Add lubricating oil; ④ Check and adjust the supply voltage. |
6. The vibration of the running electric motor is quite violent. | ① The big gap caused by the bearing abrasion; ② Uneven air gap; ④ Rotor unbalance; ⑤ Rotating shaft bending; ⑥ Coaxiality of the coupling (belt pulley) is too low. | ① Check and repair the bearing or change when necessary; ②Balance correction; ③ Bearing correction; ④ Correct again so that it can meet the standard. |
7. Overheated bearing. | ① The lubricating oil is too much or too little; ② There are impurities in the lubricating oil; ③ The bearing and the shaft neck or end cover is not matching (too loose or too tight); ④ The inner bore of the bearing is off center, so there is friction between the bore and shaft; ⑤ The motor end cover and the shaft cover is not flat; ⑥ The motor and the loaded coupling is not corrected, or the belt is too tight; ⑦ The bearing clearance is too large or too small; ⑧ The electric motor shaft bending. | ① Add lubricating oil according to the regulation (solvent 1/3-2/3); ② Change into the clean lubricating oil; ③ If it is too loose, you can repair it with binder; if it is too tight, you can make it suitable by grinding the shaft neck or inner bore of the end cover; ④ Change the bearing; ⑤ Assemble again; ⑥ Correct again, adjust the belt tension; ⑦ Change into a new bearing; ⑧ Motor shaft correction or rotor replacement. |
8. Overheated or even smoking electric motor. | ① The supply voltage is too high; ② The supply voltage is too low, the electric motor operates with rated load, too large electric current will cause the heat of winding; ③ The heat removing method which is used to repair and remove the winding is not proper, so the iron core is burnt down; ④ The motor is overloaded or started up too frequently; ⑤ Lack of phase, operate with only two phases; ⑥ After the rewinding, the impregnation of stator winding is insufficient; ⑦ High environment temperature, lot of dirt on the surface of the electric motor or blocking of air shaft. | ① Reduce the supply voltage (such as adjusting the tapping point of the supply transformer); ② Increase supply voltage or adopt thicker supply conductor; ③ Check the iron core for troubleshooting; ④ Load shedding; control the start-up times within the specified number of times; ⑤ Restore 3 phase operation; ⑥ Adopt secondary impregnation and vacuum impregnation; ⑦ Clean the motor, improve environment temperature by adopting cooling measure. |