Structural Characteristics And forms Of Dry-Type Transformers

10-10 2024 | By:

Dry-type transformer: Relying on air convection for cooling, it is generally used for small-capacity transformers such as local lighting and electronic circuits, with a transformation ratio of 6000V/400V and a load with a rated voltage of 380V. Simply put, a dry-type transformer refers to a transformer whose core and winding are not immersed in insulating oil.

The structure can be divided into two types: (1) solid insulation encapsulated winding (2) non-encapsulated winding

Structural features of dry-type transformers:

1. The core is made of high-quality cold-rolled grain-oriented silicon steel sheets, and the core silicon steel sheets use 45-degree full-bevel seams to allow the magnetic flux to flow along the seams of the silicon steel sheets.

2. Windings are of the following types:

(1) Wrapping

(2) Epoxy resin plus stone should be filled with sand

(3) Glass fiber reinforced epoxy resin casting (i.e. thin insulation structure)

(4) Multi-strand glass fiber impregnated epoxy resin winding (usually 3 types are used because it can effectively prevent the cracking of the casting resin and improve the reliability of the equipment)

3. High-voltage windings generally adopt multi-layer cylindrical or multi-layer segmented structures

4. Low-voltage windings generally adopt layer or foil structures

Dry-type transformer forms:

1. Open. It is a commonly used form. Its body is directly in contact with the atmosphere. It is suitable for relatively dry and clean indoors (ambient temperature 20 degrees, relative humidity not exceeding 85%). There are generally two types of air self-cooling and air cooling.

2. Closed. The body is in a closed shell and is not in direct contact with the atmosphere. (Due to sealing. The heat dissipation conditions are poor. Mainly used for mining and explosion-proof)

3. Casting. Epoxy resin or other resins are used as the main insulation, with a simple structure and small size. Suitable for transformers with smaller capacity.

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