Analysis of common faults of the hottest motor

Analysis of common faults of motors

three phase asynchronous motors are widely used, but after long-term operation, various faults will occur. It is an important work to prevent the expansion of faults and ensure the normal operation of equipment to judge the causes of faults in time and deal with them accordingly

I. the motor cannot rotate after being powered on, but there is no abnormal sound, odor and smoke

nearly 40 listed companies accelerated the layout of lithium battery business. 1. Cause of failure ① the power supply is not connected (at least two phases are not connected); ② Fuse fusing (at least two phases fusing); ③ The overcurrent relay is adjusted too small; ④ Wrong wiring of control equipment

2. Troubleshooting ① check whether there are breakpoints at the power circuit switch, fuse and junction box, and repair them; ② Check the fuse model and cause, and replace the fuse; ③ Yang Gong taught the purpose and function of standard compilation, and the coordination between relay setting value and motor; ④ Correct the wiring

II. The motor does not rotate after being powered on, and then the fuse burns out

1. Fault cause ① lack of one phase power supply, or the fixed dry coil is connected in the opposite direction; ② Phase to phase short circuit of stator winding; ③ Stator winding grounding; ④ Stator winding wiring error; ⑤ The fuse section is too small; ⑤ The power line is short circuited or grounded

2. Troubleshooting ① check whether one phase of the knife switch is not closed well, but one phase of the power circuit is disconnected; Eliminate reverse connection fault; ② Find out the short-circuit point and repair it; ③ Eliminate grounding; ④ Find out the wrong connection and correct it; ⑤ Replace the fuse; ③ Eliminate the grounding point

III. the motor does not rotate after being powered on, and there is a buzzing sound

l. fault cause ① stator and rotor windings have open circuit (one phase is disconnected) or one phase of the power supply loses power; ② The beginning and end of the winding outgoing line are connected incorrectly or the internal connection of the winding is reversed; ③ The contact of power circuit is loose and the contact resistance is large; ④ The motor load is too large or the rotor is stuck; ⑤ The power supply voltage is too low; ⑥ The assembly of small motors is too tight or the grease in the bearings is too hard; ⑦ The bearing is stuck

2. Troubleshooting ① find out the breaking point and repair it; ② Check the polarity of the winding; Judge whether the winding end is correct; ③ Tighten the loose wiring screws, use a multimeter to judge whether each joint is false, and repair it; ④ Reduce the load or find out and eliminate mechanical faults, ⑤ check whether the specified surface connection method is wrongly connected to y; Whether the voltage drop is too large due to the too thin power conductor, correct it, ⑥ reassemble it to make it flexible; Replace qualified grease; ⑦ Repair the bearing

IV. the motor is difficult to start, and the motor speed is much lower than the rated speed at rated load

1. Fault cause ① the power supply voltage is too low; ② The motor of face connection method is wrongly connected as y; ③ Open welding or fracture of cage rotor; ④ Local coils of stator and rotor are wrongly connected and inversely connected; ③ Too many turns are added when repairing the motor winding; ⑤ The motor is overloaded

2. Troubleshooting ① measure the power supply voltage and try to improve it; ② Correct the connection method; ③ Check open welding and breakpoints and repair them; ④ Find out the wrong connection and correct it; ⑤ Restore the correct number of turns; ⑥ Load shedding

v. the no-load current of the motor is unbalanced, and the three-phase difference is large

1. Fault cause ① when rewinding, the turns of the three-phase windings of the stator are not equal; ② Wrong connection of winding ends; ③ Unbalanced power supply voltage; ④ There are faults in the winding, such as softening short circuit, coil reverse connection, etc

2. Troubleshooting ① rewind the stator winding; ② Check and correct; ③ Measure the power supply voltage and try to eliminate the imbalance; ④ Clear the winding fault

VI. when the motor is unloaded and overloaded, the ammeter pointer is unstable and swings

1. Fault cause ① the cage rotor guide bar is disconnected, and there are wear-resistant tests or broken bars; ② Winding rotor fault (one phase open circuit) or poor contact of brush and collector ring short circuit device

2. Troubleshooting ① find out the broken bar and repair it or replace the rotor; ② Check the circuit around the rotor and repair it