H-Class lmpregnated Insulated Dry-type Transformer

Insulation

• Class H insulation refers to the maximum temperature rating of the transformer’s insulating materials. This class can withstand temperatures up to 180°C (356°F). In comparison, other insulation classes like Class F and Class B have lower temperature ratings, making Class H transformers suitable for more demanding environments where higher thermal tolerance is required.
• Impregnated insulation involves the use of insulating resin that is impregnated into the windings and core. This process helps enhance the insulation properties and prevents moisture and contaminants from affecting the transformer’s performance. The impregnation process ensures high electrical resistance, better thermal dissipation, and greater overall reliability.

Impregnation Process

• The windings and core are soaked in an insulating resin (often epoxy or polyester-based) under vacuum or pressure. This process enhances the mechanical strength and dielectric properties of the transformer.
• This impregnation method helps to prevent the formation of air gaps, improving the reliability and efficiency of the transformer, especially in high-load applications.

Maintenance:

• These transformers are low-maintenance compared to oil-filled ones because they don’t require regular oil checks or replacements. However, they still need to be inspected periodically for dust, dirt, and any signs of damage to the insulation.