1. Check if there is any obvious abnormality by observing the appearance of the transformer. If the coil lead is broken, de-soldering, whether the insulating material has burnt marks, whether the iron-tightening screw is loose, whether the silicon steel sheet is rusted, whether the winding coil is exposed or the like.
2. Insulation test. Use the multimeter R×10k block to measure the resistance between the core and the primary, the primary and the secondary, the core and each secondary, the electrostatic shielding layer and the secondary and secondary windings. The multimeter pointer should refer to the infinity position. move. Otherwise, the transformer insulation performance is poor.
3. Detection of coil on and off. Place the multimeter in the R×1 gear. During the test, if the resistance value of a winding is infinite, the winding has a faulty fault.
4. Discriminate between the primary and secondary coils. The primary and secondary pins of the power transformer are generally led out from both sides, and the primary winding is marked with 220V, and the secondary winding is labeled with rated voltage, such as 15V, 24V, 35V. Then identify them based on these markers.
5. Detection of no-load current.
6. Generally, the low-power power transformer allows the temperature rise to be 40 °C ~ 50 °C. If the quality of the insulating material used is good, the temperature rise can be increased.
7. Detect and identify the same name end of each winding. When using a power transformer, sometimes two or more secondary windings can be used in series in order to obtain the required secondary voltage. When the power transformer is used in series, the same name of each winding participating in the series must be correctly connected, and no mistake can be made. Otherwise, the transformer will not work properly.
8. Comprehensive detection and identification of short-circuit faults of power transformers. The main symptoms after a short-circuit fault in the power transformer are severe heat generation and abnormal secondary winding output voltage. Generally, the more short-circuit points between the turns inside the coil, the greater the short-circuit current, and the more severe the transformer heats up. A simple way to detect if a power transformer has a short-circuit fault is to measure the no-load current (tested earlier in the test method). A transformer with a short-circuit fault will have a no-load current value that is much greater than 10% of the full-load current. When the short circuit is severe, the transformer will heat up quickly within a few tens of seconds after the no-load power is applied. Touching the iron core by hand will have a hot feeling. At this time, it is not necessary to measure the no-load current to conclude that the transformer has a short-circuit point.
2. Insulation test. Use the multimeter R×10k block to measure the resistance between the core and the primary, the primary and the secondary, the core and each secondary, the electrostatic shielding layer and the secondary and secondary windings. The multimeter pointer should refer to the infinity position. move. Otherwise, the transformer insulation performance is poor.
3. Detection of coil on and off. Place the multimeter in the R×1 gear. During the test, if the resistance value of a winding is infinite, the winding has a faulty fault.
4. Discriminate between the primary and secondary coils. The primary and secondary pins of the power transformer are generally led out from both sides, and the primary winding is marked with 220V, and the secondary winding is labeled with rated voltage, such as 15V, 24V, 35V. Then identify them based on these markers.
5. Detection of no-load current.
6. Generally, the low-power power transformer allows the temperature rise to be 40 °C ~ 50 °C. If the quality of the insulating material used is good, the temperature rise can be increased.
7. Detect and identify the same name end of each winding. When using a power transformer, sometimes two or more secondary windings can be used in series in order to obtain the required secondary voltage. When the power transformer is used in series, the same name of each winding participating in the series must be correctly connected, and no mistake can be made. Otherwise, the transformer will not work properly.
8. Comprehensive detection and identification of short-circuit faults of power transformers. The main symptoms after a short-circuit fault in the power transformer are severe heat generation and abnormal secondary winding output voltage. Generally, the more short-circuit points between the turns inside the coil, the greater the short-circuit current, and the more severe the transformer heats up. A simple way to detect if a power transformer has a short-circuit fault is to measure the no-load current (tested earlier in the test method). A transformer with a short-circuit fault will have a no-load current value that is much greater than 10% of the full-load current. When the short circuit is severe, the transformer will heat up quickly within a few tens of seconds after the no-load power is applied. Touching the iron core by hand will have a hot feeling. At this time, it is not necessary to measure the no-load current to conclude that the transformer has a short-circuit point.
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