The temperature rise of the motor does not change during normal operation and is within the specified temperature rise allowable range. If an enterprise uses high-power motors, if the temperature rise is too high, or compared with similar high-power motors under the same working conditions, the temperature is obviously unusually high, it should be a hindrance.
When the high-power motor is running, the temperature rises too high, which not only shortens the service life, but also causes a fire alarm in severe cases. Overheating of high-power motors is often a comprehensive indication before the motor hinders, and it is also the main cause of motor damage. If the motor is overheated, the first thing to look for is the heat source, which is equal to which component’s fever is causing, and then find out the cause of the overheating of these components.
The reasons for the excessive temperature rise are as follows:
1. The load of the high-power motor is too large
If the drive belt of the dragging machine is too tight and the rotating shaft does not move, it may cause the motor to run permanently overloaded. At this time, the machine maintenance personnel should be asked to properly loosen the transmission belt, disassemble and check the rotation of the machine and equipment, and try to adjust the load to keep the motor running under the rated load.
2. The motor is in bad condition
If the motor is exposed to the sun, the temperature of the situation is higher than 40℃, or it is operated under the condition of poor ventilation, it will cause the temperature of the motor to rise. It can be shaded by a shallow pergola or blower or electric fan. Pay attention to removing oil and dust from the motor's own air duct to improve cooling conditions.
3. The power supply voltage is too high or too low
The rated power can be kept stable when the motor is running in the range of power supply voltage conversion -5%-+10%. If the power supply voltage is higher than 10% of the rated voltage, it will cause the core magnetic flux density to increase sharply, increase the iron loss and cause the motor to overheat. The key to detailed investigation is to use an exchange voltmeter to measure the bus voltage or the terminal voltage of the motor. If it is due to the grid voltage, it should be reported to the power supply part; if the circuit voltage drop is too large, a larger cross-sectional area of the wire should be changed and the motor and power supply should be shortened. Interval.
4. Power failure: If the power supply is interrupted and the motor runs in a single phase, it will cause the winding of the motor to become abruptly feverish in a short time and cause burning. Therefore, check the fuse and switch status of the motor first, and then use a multimeter to measure the front line.
5. The cage rotor guide bar is broken, welded or the cross-sectional area of the rotor guide bar is too small, which will increase the loss and cause a fever. You can test the rotor temperature after stopping the machine to find the cause of the obstacle and remove it.
6. If the motor starts frequently or the number of forward and reverse rotations is too much, the motor starts frequently or the number of forward and reverse rotations is too much, the number of starting times should be limited, and the overheating protection should be selected correctly or the motor suitable for production requirements should be changed.