Comparison of different temperature measurement methods for motor windings
The temperature rise of the winding is an important performance index of the motor. The calculation of the temperature rise of the motor is based on the resistance method, that is, the temperature rise of the winding is calculated according to the change of the DC resistance of the winding. Another method is to use the temperature measuring component for detection. .
When the electric resistance method is applied to the motor type test, the temperature rise of the motor can be calculated objectively and accurately. However, the detection of the hot resistance is performed when the motor is stopped. The final test result deviates slightly from the actual one, but the electric resistance method can It is relatively accurate to reflect the overall temperature rise effect of the winding, so it is relatively accurate.
The detection method using the temperature measuring component is mainly a monitoring requirement after the motor is put into use, one is the detection of the temperature rise of the winding, and the other is the monitoring of the bearing temperature. This method is for dynamic monitoring and measurement under the condition of motor operation. The measured data should be more timely, and it can also be associated with the control device according to the preset setting to protect the temperature of the motor winding. However, the position at which the temperature measuring element is placed is directly related to the temperature finally displayed, that is, the result of detecting with the temperature measuring element is uncertain.
1, resistance method to measure temperature rise
The resistance method is to measure the temperature of the coil by using the change of the resistance of the coil during heating. The specific method is to determine the temperature of the coil by using the DC resistance of the coil and the corresponding increase in the resistance value after the temperature rises. The average value of the temperature. Within a certain temperature range, the resistance value of the motor coil will increase correspondingly with the increase of temperature, and there is a certain functional relationship between the resistance value and the temperature.
2, temperature measuring components
The so-called temperature measuring component is the detecting component of the temperature measuring instrument. Such as thermocouples, thermal resistors, thermistors, etc. The temperature measured by the contact temperature measuring instrument is determined by the temperature felt by the temperature measuring element. It is an important practical problem to correctly install the temperature measuring element after selecting the temperature measuring element and the secondary instrument that are both economical and reasonable, and can meet the requirements for the precision required for production. If the meter installation does not meet the requirements, the measurement data will be distorted.
