the cooling system failure
➤Flame damage
➤The fan is not fastened
Hurricane blockage
Hurricane temperature is not normal
According to the infrared thermal image analysis: the surface temperature of the whole motor stator is almost the same, and the surface of the motor stator has no convection cooling caused by the tail end heat dissipation system. Therefore, it can be confirmed that such a fault is a poor heat dissipation.
Motor cooling system, when testing in the field, we may encounter:
If the actual test at the site, the temperature distribution of the motor junction box shell is abnormal, local heating, the shell temperature may not be high, but must pay attention!
According to Stefan-Boltzmann's law / StefanBlotzmann Law: J = ε * δ * T4. The thermal radiation is approximately equal to the fourth power of the temperature T. Therefore, the internal fault of the motor is thermally conducted to the surface of the motor casing, and there is a more obvious thermal gradient display.
After opening, we found that the inside of the junction box was filled with water and the cable connector was oxidized. It should be adjusted immediately.
For the motor manufacturer, you need to know the internal temperature of the motor, what should we do?
Although the thermal imaging camera cannot measure the precise temperature inside the motor, the temperature inside the motor can be easily calculated based on the temperature distribution of the outer surface of the motor.
Let's take a look at the detection example:
We are going to test the temperature of a Class B motor. Its maximum temperature limit is 80 °C. We first test the highest temperature of the motor's outer surface with a thermal imager, and then use a contact type K-type thermocouple temperature probe to access the internal area corresponding to the high temperature of the outer surface (note the insulation).
After that, the temperature of the motor is tested by a thermal imager and a contact thermocouple. After the temperature is stabilized, the temperature difference between the thermal imager and the thermocouple is calculated. This temperature difference is the correction value. Through the test we learned:
The temperature difference between the surface and the inside of the B-class motor is generally around 25 ° C to 30 ° C. Therefore, as long as the external surface temperature of the B-class motor is stable below 50 °C-60 °C, the normal operation of the motor can be guaranteed!
Please note: the internal space and temperature of the motor with different insulation levels are different. If the insulation level of the motor under test changes, you can recalculate the correction value according to the above steps.
If you want to buy a medical device motor, please pay attention to AC Synchronous Motors.
