The quality of high-frequency transformers can be judged through a series of measurement steps, and the following are some commonly used measurement methods:

1、 Appearance inspection

Firstly, conduct a visual inspection to see if the appearance of the high-frequency transformer has the following conditions:

Whether the winding leads are broken or detached.

Is there any crack, damage or looseness in the magnetic core.

If these situations exist, it will affect the performance of the transformer and even prevent it from working properly, which can be judged as damage.

2、 Measurement of winding resistance

Measure the resistance values of each winding of the high-frequency transformer using the resistance range of the multimeter. The winding resistance of transformers of different specifications varies, but under normal circumstances, the winding resistance should have a certain value. The specific criteria for judgment are as follows:

If the measured resistance is infinite, it indicates that the winding is open and the transformer is damaged.

If the resistance value differs significantly from the standard value, there may be a short circuit or other fault in the winding.

3、 Insulation resistance measurement

Measure the insulation resistance between windings and between windings and the iron core (or shell) using a megohmmeter. The insulation resistance should be above several hundred megaohms. If the insulation resistance is low, it indicates poor insulation performance of the transformer, which may be affected by moisture or damage to the insulation layer, which will affect its normal operation and safety.

4、 Inductance measurement

Measure the inductance of each winding using an inductance tester. The inductance must meet the design specifications of the transformer. If the inductance deviation is too large, even if the winding resistance and insulation resistance are normal, it will affect the performance of the transformer and prevent it from working properly.

5、 Interturn short circuit detection

Interturn short circuits are difficult to measure directly and can be determined by the following methods:

Connect the primary winding of the transformer to the rated voltage and measure the no-load current with an ammeter. If the no-load current is much larger than the normal value, there may be a turn to turn short circuit.

Using a specialized inter turn short circuit tester can more accurately detect whether there is a short circuit between turns.

6、 Other measurement methods

Measurement of no-load current: Measure the no-load current of high-frequency transformers. The smaller the no-load current, the better the quality of the iron core, and the design of ampere turns is very reasonable.

Copper loss measurement: The copper loss of high-frequency transformers refers to the loss caused by the DC resistance of the primary and secondary wires. By adding the rated current, the voltage at this time can be measured and the loss can be calculated. The smaller the loss, the lower the resistance value of the enameled wire, and the load rate of this high-frequency transformer is inevitably higher.

Frequency characteristic measurement: Use a spectrum analyzer to measure the response of transformers at different frequencies to evaluate their frequency characteristics.

Temperature rise measurement: After the transformer has been working for a period of time, measure its temperature rise to evaluate its thermal stability. If the measured temperature rise is abnormally high, it may be due to damage to the iron core.

7、 Precautions

The above detection methods need to be used in combination to comprehensively judge the quality of high-frequency transformers.

Be sure to pay attention to safety during testing, operate under power-off conditions, and avoid electric shock.

By comprehensively applying the above measurement methods, the performance and status of high-frequency transformers can be effectively evaluated, ensuring their stable operation in electronic devices.