In the field of industrial production, domestic servo explosion-proof motors are widely used in flammable and explosive environments such as chemical and mining industries due to their strong adaptability and high safety factor. However, during long-term high load operation, overload and abnormal noise become two types of high-frequency faults, which not only affect production efficiency but may also cause safety hazards. Mastering scientific investigation methods and solution strategies is the key to ensuring the stable operation of equipment.
1、 Overload fault: Investigation from the dual dimensions of load and motor itself
Overload is the most easily triggered protection mechanism for servo explosion-proof motors, manifested as frequent motor start stop, sudden speed drop, and in severe cases, triggering overheating alarm. The core causes can be divided into two categories: external load abnormalities and motor problems.
When troubleshooting external loads, the first step is to check if the transmission system is stuck. The connection between the motor and the load can be disconnected, and the coupling or conveyor belt can be manually rotated. If there is obvious resistance, it may be due to bearing rust, lack of oil in the gearbox, or foreign object blockage. It needs to be disassembled, cleaned, and supplemented with special lubricating oil; Secondly, it is necessary to confirm whether the load parameters match. Some companies temporarily increase equipment load due to production needs, resulting in the actual output torque of the motor exceeding the rated value. At this time, it is necessary to check the rated power and torque parameters on the motor nameplate, and if necessary, replace the motor with a higher specification or optimize the production process to disperse the load pressure.
The troubleshooting of motor problems needs to focus on three major components: first, the power supply voltage. Use a multimeter to check whether the input voltage is stable within the rated range (usually 380V ± 5%). If the voltage is too low, it will cause a surge in motor current. It is necessary to check whether the contactor contacts in the distribution box are oxidized and polish or replace them in a timely manner; The second is the insulation performance of the winding. A megohmmeter is used to measure the insulation resistance of the winding to ground. If the value is lower than 0.5M Ω, it may be due to moisture or local short circuit of the winding, and it needs to be dried. In severe cases, the winding needs to be rewound; The third is the cooling system. The cooling fins of explosion-proof motors are prone to dust accumulation, which can block the cooling channels. Therefore, it is necessary to regularly blow with compressed air to ensure the normal operation of the cooling fan.
2、 Abnormal noise fault: locate the fault source based on sound characteristics
Abnormal noise is a visual signal of internal abnormalities in the motor, and there are significant differences in the types of faults corresponding to different sounds. It is necessary to combine auscultation and disassembly for troubleshooting.
If the motor emits a buzzing electromagnetic noise during operation, it is mostly caused by uneven air gap. Measure the air gap between the stator and rotor of the motor after shutdown. The normal range should be 0.2-0.5mm. If the deviation exceeds 0.1mm, adjust the position of the bearing end cover or replace the worn bearing; If there is a "clunking" mechanical impact sound, it may be due to broken rotor bars or loose fan blades. After disassembling the motor, check whether the rotor guide bars are broken, whether the connection between the fan and the shaft is firm, and whether the broken parts need to be welded or replaced in a timely manner.
In addition, improper installation can also cause abnormal noise. Excessive coaxiality deviation between the motor and the load can cause eccentric wear of the coupling and periodic abnormal noise during operation. A dial gauge can be used to measure coaxiality, with a radial deviation of ≤ 0.1mm and an axial deviation of ≤ 0.05mm. If the deviation exceeds the limit, the base gasket needs to be readjusted to ensure alignment of the two axes.
3、 Daily prevention: the key to reducing the occurrence rate of failures
In addition to troubleshooting, daily maintenance can effectively reduce overload and abnormal noise problems. Regularly clean the dust on the surface of the motor and the heat dissipation channel, check the lubrication of the bearings every 3-6 months, and replenish lithium based grease; Regularly calibrate the parameters of the servo drive according to changes in production load to avoid the motor from running at over rated torque for a long time; Establish an equipment operation ledger to record the number of motor starts and stops, temperature changes, and abnormal noise situations, in order to predict the risk of faults in advance.
The overload and abnormal noise faults of domestic servo explosion-proof motors are often caused by load mismatch, component wear, or improper installation. By using a systematic troubleshooting process to locate the source of the fault, combined with targeted solutions, and strengthening daily maintenance, the stability of motor operation can be significantly improved, providing a guarantee for the safety and efficiency of industrial production.