Under what circumstances can the bushing of a transformer be removed original Light of Devices

Transformer bushing will increase its process difficulty and reduce production efficiency. The PTFE casing still faces the problem of difficult degradation. More and more transformers are eliminating the bushing process.

So, the question is: under what circumstances can the bushing of a transformer be removed?
At this point, we need to look back at the function of transformer bushing: 1. Ensuring safety distance; 2. Ensure the withstand voltage capability between windings; 3. Provide reliability of the transformer.

As long as the transformer does not have a bushing, these requirements can be met. So, the transformer can naturally eliminate the bushing.
In terms of ensuring safety distance and improving voltage resistance, we can use a safety framework to extend the width of the framework and the height of the baffle to ensure the distance between the primary and secondary, and between the primary and magnetic cores of the transformer. This is particularly commonly used in automation frameworks.
For the melting loss caused by wire soldering process, it can be met by increasing the melting distance margin, controlling the soldering temperature and time.

For three-layer insulated wires with severe melting loss during the soldering process, a stripped three-layer insulated wire can be used to meet the corresponding requirements. Stripped three-layer insulated wire can be treated with laser peeling, greatly reducing the soldering time and temperature, and minimizing melting loss.
For multi strand or wire wrapped wires, film wrapped wires can be used instead to prevent excessive melting during the soldering process. Its basic logic is similar to that of stripped three-layer insulated wires.

Some transformer products can also change the winding slot position, increase the routing length between the PIN soldering position and the winding, and increase the margin of melting loss to meet the withstand voltage requirements.
In terms of the reliability of transformers, some products will add adhesive treatment at the transformer pins to prevent the winding wires from breaking after soldering.
In practical applications, we need to make judgments based on the withstand voltage and reliability requirements of transformers. Many low-voltage and low current products can eliminate the bushing if the distance meets the requirements. For products with high voltage and high current, caution should be exercised.