Power transformers play an extremely important role in the safety of most medical electrical equipment. If the equipment transformer fails during operation, the temperature of the transformer winding will rise too high. Exceeding the maximum temperature that its material parts can withstand may cause transformer insulation failure, causing electric shock and fire hazards. Therefore, it is important to pay attention to the thermal protection of the transformer.

The customer is a transformer manufacturer, in order to help customers choose the most suitable temperature switch. We conducted simulation experiments according to the customer's use environment: short circuit experiment and overload experiment. In the short circuit experiment, we measured the temperature change of the winding. And according to the data, you can know which part of the protection device is working, and then carry out an overload test based on this result. When carrying out an overload experiment, continue to increase the current to the temperature switch until the maximum value of the temperature switch inactivity is measured. Through these two experiments, the most suitable temperature protection parameters are obtained. It should be noted that there is a certain deviation between the winding temperature when the temperature switch is operating and the nominal operating temperature of the temperature switch. This is related to the response speed, accuracy, and location of the temperature switch.

Transformers commonly use self-resetting temperature switches, the models are TB02, HCET-A miniature temperature switches. The circuit is turned on and off by temperature sensing, thereby playing a thermal protection role. The operating temperature error is generally ±5˚C, the reset temperature is generally lower than the operating temperature by 20˚C, and the error is about ±10˚C.

When selecting the temperature switch of the power supply and transformer, care should be taken to select the specifications suitable for the working voltage and working current of the transformer. When installing, try to place it at the innermost end of the winding and fit it tightly. When soldering, pay attention to the good lead connection to prevent the virtual connection from generating heat and affecting the normal operation of the temperature control switch.