Electric motors are indispensable components in the hydraulic system, and many motors often work overloaded in hydraulic stations. Therefore, there may be incidents of motor burnout during operation. Burning out the motor can cause all hydraulic systems to fail to function, seriously affecting production safety. What are the factors and solutions for hydraulic system motor burnout?

 

 

 

1、 Due to prolonged overload or overheating, the aging of the winding insulation accelerates, and the carbonization of the thinnest insulation defect leads to inter turn short circuit, phase short circuit, or ground short circuit, causing some burning of the winding.

 

resolvent:

 

① Try to avoid overloading the motor.

 

② Ensure that the motor is clean and well ventilated for excellent heat dissipation.

 

③ To avoid repeated starting of the motor, it is necessary to conduct dynamic balance experiments on the motor rotor when necessary.

 

 

 

2、 Phase loss operation

 

At this point, the noise of the motor is very loud and it generates severe heat, which is also the fatal killer of three-phase asynchronous motors. Generally, they burn out after working for more than ten minutes. If all power supply systems are out of phase, it is highly likely that multiple motors will be damaged. Lack of phase often refers to the burning phenomenon of a certain phase or two phases. Single-phase operation is caused by an open circuit in one phase of the motor power supply, which is often caused by burnt fuses, poor electromagnetic contactors, disconnected power lines, or poor wiring.

 

resolvent:

 

There are many methods and equipment for motor phase failure protection, and there are a lot of online searches. Xuli Hydraulic introduces the commonly used protection methods as follows: selecting thermal relays with phase failure protection equipment for phase failure protection; Reverse current relay phase failure protection; Zero sequence voltage relay phase failure protection; Broken wire voltage relay phase failure protection; Use fast saturation current transformer protection, etc.

 

 

 

3、 The insulation of motor winding is subject to the effect of mechanical vibration (such as high current impact when starting, imbalance of motor rotor, etc.), resulting in inter turn relaxation, insulation cracks and other undesirable phenomena in the winding. The damage effect is constantly piling up. thermal expansion make the winding subject to friction, and then accelerate the insulation aging. After all, the earliest carbonized insulation is damaged until the winding is burned.

 

resolvent:

 

① Try to avoid repeated starts, especially for high-voltage motors.

 

② Ensure that the vibration values of the dragged equipment and motor are within the specified range.

 

 

 

4、 The motor itself has poor sealing, resulting in erosion of the insulation of the motor winding group. The most severe or thinnest insulation defect may cause a slight ground to ground, phase to phase short circuit or turn to turn short circuit, and then cause some burning of the motor winding group

 

Motor burnout

 

resolvent:

 

① Try to eliminate equipment leakage as much as possible

 

② When repairing, pay attention to the sealing of each part of the motor. For example, apply a small amount of 704 sealant to each flange, apply grease to the bolts, and if necessary, install anti drip and splash boxes at junction boxes and other places. If the motor is exposed to liquids and dirt, a protective cover should be installed locally;

 

③ For motors working in this environment, it is necessary to shorten the cycle of minor and medium repairs, and in severe cases, timely medium repairs should be carried out.

 

 

 

V Due to bearing damage, shaft bending, and other factors, friction between the stator and rotor (commonly known as sweeping) leads to a sharp increase in core temperature, burning down slot insulation and inter turn insulation, forming a winding inter turn short circuit or "shooting" to the ground from the surface. In severe cases, it can cause the stator core to be chamfered, misaligned, the shaft to be worn, and the end cover to become invalid.

 

resolvent:

 

① When disassembling bearings, it is generally necessary to heat the bearings to 80 ℃~100 ℃, such as selecting bearing heaters, boiling transformer oil, etc. Only in this way can the equipment quality of bearings be guaranteed.

 

② It is necessary to carefully clean the equipment bearings before filling them. There should be no impurities left in the bearing cavity, and it is necessary to ensure cleanliness when adding grease.

 

③ Try to avoid unnecessary shaft machining and motor end cover nesting work.

 

④ When assembling the motor, it is necessary to ensure that the stator and rotor iron cores are aligned and not misaligned.

 

⑤ The cleanliness of the motor casing is evident, and it is necessary to ensure ventilation. The cooling equipment must not have scale buildup, and the fan blades must be kept intact.

 

⑥ Prevent the mixing of multiple lubricating greases.

 

⑦ Before starting the equipment bearing, it is necessary to conduct a thorough and flawless inspection of the bearing.

 

⑧ For motors that have not been used for a long time, it is necessary to conduct necessary collapse checks and update bearing grease before use.