Electric motors are widely used in industrial production and daily life. From mechanical equipment in factories to household appliances, their operation is indispensable. However, when the motor fails to start and stalls, it not only affects the normal operation of the equipment, but may also pose a safety hazard. What exactly caused this problem to occur? Next, we will delve into the analysis and provide corresponding solutions.

1、Mechanical malfunction

（1） Bearing damage

After prolonged use, motor bearings may experience damage such as ball wear, inner and outer ring rupture due to wear, insufficient lubrication, or external impact. This will increase the resistance of the motor operation, resulting in a sluggish start. For example, in some high load industrial motors, the wear rate of bearings will accelerate, and if not maintained in a timely manner, it is easy to cause faults. During inspection, it can be judged by listening to the sound of the motor running. If there are abnormal friction or vibration sounds, it is likely that there is a problem with the bearing. The bearing needs to be replaced in a timely manner and appropriate lubricating grease should be added regularly.

（2） Rotor sweeping chamber

Rotor sweeping refers to the uneven air gap between the rotor and stator of a motor, which causes friction between the rotor and the inner wall of the stator during rotation. The cause of rotor sweeping may be improper motor installation, bent shaft, or severe bearing wear. Once rotor sweeping occurs, it becomes difficult to start the motor and is accompanied by abnormal heating. To solve this problem, it is necessary to disassemble the motor and check if the shaft is bent. If it is bent, it needs to be corrected or replaced; Simultaneously adjust the air gap between the rotor and stator to restore them to normal.

2、Electrical malfunction

（1） Power issue

① Insufficient voltage: When the power supply voltage is lower than the rated voltage of the motor, the electromagnetic torque of the motor will decrease, resulting in weak starting. For example, during peak electricity consumption periods, due to excessive grid load, voltage fluctuations may occur, causing the motor to fail to start normally. A multimeter can be used to measure the power supply voltage. If the voltage is significantly lower than the rated value, the power supply situation of the grid should be checked, and a voltage regulator should be installed if necessary to stabilize the voltage.

② Phase loss: When a three-phase motor is running, if one of the phase power sources is missing, the motor will operate in phase loss. When there is a phase loss, the motor will make an abnormal buzzing sound when starting and cannot rotate normally. In severe cases, it may burn out the motor. To check for phase loss issues, it is necessary to inspect electrical components such as circuit breakers and contactors for poor contact or damage, and promptly repair or replace faulty components.

（2） Winding fault

① Winding short circuit: The motor winding may experience a short circuit due to insulation aging, moisture, or external damage. A short circuit in the winding will increase the motor current, cause severe heating, and result in a sluggish start. It can be determined whether there is a short circuit by measuring the DC resistance of the winding. If the resistance of one phase winding is significantly lower than that of other phases, there may be a short circuit problem, and the short circuited winding needs to be repaired or rewound.

② Winding breakage: Winding breakage can cause some coils of the motor to malfunction, resulting in electromagnetic force imbalance and difficulty in starting. To check for a broken winding, a multimeter can be used to measure phase by phase. Once the broken point is identified, the damaged winding can be reconnected or replaced.

3、Other factors

（1） Overloaded load

When the load carried by the motor exceeds its rated load, it needs to overcome greater resistance during startup, which can result in power failure and lagging. For example, blockages in the water pump and tight belts can increase the load on the motor. The solution is to check the load equipment, clean the blockage of the water pump, adjust the tightness of the belt, and ensure that the load is within the rated range of the motor.

（2） Environmental factors

Excessive temperature, humidity, or dust in the working environment of a motor can affect its performance. High temperature will accelerate the aging of motor insulation materials and reduce the efficiency of the motor; A humid environment can easily cause motor windings to become damp, leading to short circuit faults; Excessive dust can accumulate inside the motor, affecting heat dissipation and operation. Therefore, it is necessary to provide a suitable working environment for the motor, maintain good ventilation, regularly clean the dust inside the motor, and take cooling and moisture-proof measures if necessary.

The problem of motor starting failure and lagging is quite complex, involving multiple aspects such as mechanical and electrical. In actual troubleshooting, it is necessary to comprehensively consider various factors, gradually narrow down the scope of the fault, accurately identify the root cause of the problem, and solve it. If you are unable to solve it yourself, it is recommended to contact professional motor maintenance personnel in a timely manner to ensure the normal operation of the motor and equipment safety.

Hengda Electric has always been dedicated to the research and development, production, and service of various types of motors. With advanced technology and equipment, lean manufacturing processes, reliable product quality, and satisfactory after-sales service, the company provides customers with the most suitable motor professional solutions and creates greater social value.