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Inventory of the five major culprits of motor failures and their troubleshooting

Release time:

2021-03-04 16:16

In the actual application of motors, many factors can cause motor failure. This article lists the five most common reasons. Let’s take a look at what five types they are. Common motor faults and their solutions are listed later.

1. Overheating

Overheating is the biggest culprit of motor failure. In fact, the other four reasons listed in this article make the list in part because they generate heat. Theoretically, for every 10°C increase in heat, the life of the winding insulation will be halved. So, making sure your motor is running at the right temperature is the best way to extend its life.

2. Dust and pollution

Various suspended particles in the air will enter the interior of the motor and cause various hazards. Corrosive particles can wear down components, and conductive particles can interfere with component current flow. Once the particles block the cooling channels, they will accelerate overheating. Obviously, choosing the correct IP protection level can alleviate this problem to a certain extent.

3.Power supply problem

Harmonic currents caused by high-frequency switching and pulse-width modulation can lead to voltage and current distortion, overloading and overheating. This shortens the life of the motor and components and increases long-term equipment costs. In addition, surges themselves can cause overvoltage and undervoltage. To solve this problem, you must constantly pay attention and check the power supply status.

4.Moist

Moisture itself can corrode motor components. When moisture and particulate pollutants in the air mix, it is fatal to the motor and further shortens the life of the pump.

5. Improper lubrication

Lubrication is a matter of degree. Over-lubrication or insufficient lubrication can cause harm. Also, be aware of contamination issues in the lubricant and whether the lubricant used is suitable for the task at hand.

The above problems are all interrelated, and it is difficult to completely solve one of them alone. At the same time, these problems also have one thing in common:If the motor is used and maintained correctly, and the environment is properly managed, these problems can be prevented.

Let me introduce to you: common motor faults and their solutions

1. When the motor is turned on and started, the motor does not rotate but there is a buzzing sound. Possible reasons:

① Single-phase operation due to power supply connection problem.

②The carrying capacity of the motor is overloaded.

③It is stuck by the dragging machine.

④The rotor circuit of the wound motor is open or broken.

⑤ The first end position inside the stator is incorrectly connected, or there is a disconnection or short circuit.

Corresponding processing method:

(1) The power cord needs to be checked, mainly the motor wiring and fuses to see if there is any line damage.

(2) Unload the motor and start it with no load or half load.

(3) It is estimated that it is due to a fault of the towed device. Uninstall the towed device and find the fault from the towed device.

(4) Check the engagement of the brushes, slip rings and starting resistor contactors.

(5) It is necessary to re-determine the beginning and end of the three phases, and check whether the three-phase windings are broken or short-circuited.

2. Possible reasons why the motor generates heat exceeding the temperature rise standard or smokes after starting:

①The power supply voltage does not meet the standard, and the motor heats up too quickly under rated load.

②The influence of the motor operating environment, such as high humidity.

③The motor is overloaded or running in single phase.

④ Motor starting failure, excessive forward and reverse rotation.

Corresponding processing method:

(1) Adjust the motor grid voltage.

(2) Check the operation of the fan, strengthen inspection of the environment, and ensure that the environment is suitable.

(3) Check the starting current of the motor and deal with any problems in time.

(4) Reduce the number of forward and reverse rotations of the motor and promptly replace the motor that is suitable for forward and reverse rotation.

3. Possible reasons for low insulation resistance:

① Water enters the motor and becomes damp.

② There are debris and dust on the winding.

③The internal windings of the motor are aging.

Corresponding processing method:

(1) Drying treatment inside the motor.

(2) Deal with debris inside the motor.

(3) It is necessary to check and restore the insulation of the lead wire or replace the insulated wire board of the junction box.

(4) Check the aging of the windings in time and replace the windings in time.

4. Possible reasons why the motor casing is charged:

①Insulation of the motor lead wire or junction box insulated wire board.

②The winding end cover contacts the motor casing.

③ Motor grounding problem.

Corresponding processing method:

(1) Restore the insulation of the motor lead wire or replace the insulation board of the junction box.

(2) If the grounding phenomenon disappears after removing the end cover, you can add insulation to the end of the winding and then install the end cover.

(3) Reground as required.

5. Possible reasons for abnormal sound when the motor is running:

① The internal connection of the motor is incorrect, causing grounding or short circuit, and unstable current causing noise.

②The internal pump of the motor is in disrepair for a long time, or there are debris inside.

Corresponding processing method:

(1) It needs to be opened for comprehensive inspection.

(2) The extracted debris can be disposed of or replaced with 1/2-1/3 of the bearing chamber.

6. Possible causes of motor vibration:

①The ground where the motor is installed is uneven.

②The internal rotor of the motor is unstable.

③The pulley or coupling is unbalanced.

④Bending of the internal rotor.