TR#3 Averías en los transformadores
Understanding Transformer Functionality and Testing
Basics of Transformer Measurements
- The importance of understanding transformer specifications, including primary and secondary voltages, is emphasized. Often, this information is not clearly labeled on the transformers.
- Measuring resistance with a multimeter in ohm mode can help determine the number of turns (spires) in a coil; more turns typically indicate higher resistance.
- When measuring between primary and secondary terminals, infinite resistance suggests no electrical contact, indicating an open circuit or fault within the transformer.
Identifying Faults in Transformers
- If measurements show infinite resistance across various points, it indicates an open circuit condition which could be due to broken windings.
- A typical scenario involves having different resistances at various points; for example, if one side measures 125 ohms, the other should ideally measure around half that value.
Characteristics of Robust Transformers
- Transformers are described as robust devices capable of withstanding significant physical impact due to their heavy iron construction.
- Overheating can cause insulation failure in transformer windings. This may lead to short circuits if wires touch each other after insulation melts.
Short Circuits and Safety Features
- If excessive current causes insulation to melt between turns, it results in fewer effective turns leading to unexpected voltage outputs.
- Some transformers include thermal fuses that disconnect power when overheating occurs. This safety feature prevents further damage but may require replacement.
Understanding Autotransformers
- Autotransformers differ from standard transformers as they do not have isolation between input and output; thus they exhibit different resistance characteristics during testing.
- Proper functioning autotransformers will show finite resistances rather than infinite when measured correctly across terminals.
Key Takeaways for Electronics Repair