What damage will overload cause to COLD MILL Motor?

1. Electrical damage
Winding overheating:
When COLD MILL Motor is overloaded, the current will increase significantly. According to Joule's law, heat will be generated when the current passes through the conductor, causing the temperature of the motor winding to rise rapidly. Excessive temperature will accelerate the aging of the insulation material of the winding and reduce the insulation performance. For example, long-term overload operation may shorten the service life of the insulation material to a fraction of the normal situation, increasing the risk of short-circuit failure of the motor.
Winding overheating may also cause thermal decomposition of the insulation layer, releasing harmful gases and fumes. These gases and fumes will not only pollute the environment, but also may cause harm to the health of operators. At the same time, the insulation material after thermal decomposition will lose its insulation properties, causing a short circuit between the windings or between the windings and the ground, causing serious electrical failures.
Increased resistance:
As the temperature rises, the resistance of the motor winding will also increase. According to Ohm's law, the increase in resistance will lead to a further increase in current, forming a vicious circle. The increase in resistance will also reduce the efficiency of the motor, consume more electricity, and generate more heat. For example, under overload conditions, the efficiency of the motor may drop from the normal 90% to 70% or even lower, resulting in energy waste.
Increased resistance will also affect the starting performance of the motor. When starting, the motor needs to overcome greater static friction and inertia, requiring a larger starting current. If the winding resistance increases, the starting current will increase further, which may cause the voltage of the power supply system to drop, affecting the normal operation of other equipment. At the same time, excessive starting current will also cause greater damage to the windings and insulation of the motor.
Degradation of electromagnetic performance:
Overload will cause the magnetic field of the motor to distort, affecting the electromagnetic performance of the motor. Magnetic field distortion will cause the torque fluctuation of the motor to increase, the speed to be unstable, and even the phenomenon of losing step. For example, during the cold rolling process, the unstable speed of the motor will affect the quality and production efficiency of the plate, and in severe cases may cause production interruption.
Magnetic field distortion will also increase the iron loss and copper loss of the motor. Iron loss is due to the eddy current and hysteresis loss generated by the magnetic field in the iron core, and copper loss is due to the resistance loss generated by the current passing through the winding. Under overload conditions, the magnetic field strength increases, and the iron loss and copper loss will also increase accordingly, further aggravating the heating and energy loss of the motor.
2. Mechanical damage
Bearing damage:
When the COLD MILL Motor is overloaded, it will generate large torque and axial force, which will be transmitted to the bearing through the transmission system. Excessive force will cause excessive pressure between the rolling element and raceway of the bearing, resulting in increased bearing wear. For example, the service life of the bearing may be tens of thousands of hours under normal circumstances, but it may be shortened to thousands or even hundreds of hours under overload conditions.
Bearing wear will cause the gap to increase, which will increase the vibration and noise of the motor. In severe cases, the bearing may get stuck or cracked, making the motor unable to operate normally. At the same time, bearing damage may also damage the shaft and end cover of the motor, increasing maintenance costs.
Shaft deformation:
The huge torque generated by overload will cause the motor shaft to be subjected to excessive stress. If the stress exceeds the yield strength of the shaft material, the shaft will undergo plastic deformation. For example, the shaft may bend, twist or break. Shaft deformation will affect the dynamic balance of the motor, causing the motor to vibrate violently during operation, further damaging other components.
Shaft deformation will also affect the accuracy and stability of the transmission system. During the cold rolling process, the accuracy of the transmission system directly affects the thickness and flatness of the plate. If the shaft is deformed, the gap in the transmission system will increase, causing the quality of the plate to decline. At the same time, an unstable transmission system may also cause damage to the cold rolling equipment, increasing maintenance costs and downtime.
Fan damage:
COLD MILL Motor is usually equipped with a fan for heat dissipation. When the motor is overloaded, the temperature rises, and the fan needs to run at a higher speed to dissipate heat. Excessive speed will cause the fan blades to bear greater centrifugal force, which may cause the blades to break or deform. For example, after the fan blades break, they may damage the motor housing or other components, causing more serious failures.
Fan damage will also affect the heat dissipation effect of the motor. If the heat dissipation is poor, the temperature of the motor will further increase, aggravating electrical and mechanical damage. At the same time, high temperature will also increase the ambient temperature around the motor, affecting the normal operation of other equipment.
3. Other damages
Production interruption:
When the COLD MILL Motor fails due to overload, it will cause the cold rolling production line to shut down. Production interruption will not only affect the output and quality of the product, but also bring huge economic losses to the enterprise. For example, in some cold rolling enterprises with continuous production, the hourly downtime loss may be as high as hundreds of thousands or even millions of yuan.
Production interruption will also affect the reputation and market competitiveness of the enterprise. If production cannot be resumed in time, it may lead to delays in customer orders and affect the cooperation relationship between the enterprise and customers. At the same time, competitors may take the opportunity to seize market share, which will have an adverse impact on the development of the enterprise.
Safety hazards:
Overload may cause serious accidents such as fire and explosion in the motor, which will bring huge safety hazards to operators and equipment. For example, when the motor winding is overheated or the insulation layer is damaged, a short-circuit arc may be triggered, which will cause a fire. If there are flammable materials around the motor, the fire may spread rapidly and cause serious consequences.
Overload may also cause the motor to produce strong vibration and noise, which will harm the health of the operator. Operators may suffer from hearing loss and neurasthenia after long-term exposure to high noise environment. At the same time, severe vibration may also cause the equipment to loosen and fall off, posing a threat to the safety of operators.
If you want to know the damage caused by overload to COLD MILL Motor, please pay attention to www.mill-motor.com!