Transformer Insulating Varnish
Air-drying and baking insulating varnishes for low and medium voltage transformers, together with pole and insulating paints.
- LV / MV transformer windings
- Air-drying or baking options
- Transformer exterior paints
Technical information
| Use | Low and medium voltage (LV / MV) transformer windings |
|---|---|
| Curing | Air-drying or baking options |
| Thermal class | Chosen to match the transformer; per product in the TDS |
| Complementary products | Pole and insulating paints, transformer exterior paints |
Drying time, viscosity, solids content, packaging and shelf life are given in the product's technical data sheet (TDS). Request the TDS and safety data sheet (SDS) via WhatsApp.
How to choose a transformer varnish
Three questions decide the choice: the transformer's thermal class, whether it is oil-filled or dry-type, and whether your workshop has an oven.
- Thermal class: The varnish class must be at least equal to the winding class (B 130 °C, F 155 °C, H 180 °C). Heavy-duty and dry-type transformers usually need class H.
- Oil-filled transformers: The winding runs in hot oil, so the varnish must resist it. Baking varnish OR 3xx is resistant to hot transformer oil.
- Oven: With an oven, baking varnish gives the highest bond strength. Without one, use air-drying options; for class H work, ask us about OR-114.
Application
- Clean the winding and preheat it to remove moisture.
- Thin the varnish with its own thinner at the ratio given in the TDS.
- Impregnate by dipping or work it well between the turns; let the excess drain.
- Dry air-drying products for the time in the TDS; bake baking products on the recommended temperature–time schedule.
Exterior and pole paints
Insulating and exterior paints for the transformer tank and pole points are available from the same supplier. Write to us for colour and product selection.
Which varnish is right for you?
Tell us your motor type, operating temperature and application method, and we will send the suitable Orchem varnish and its TDS.
Frequently Asked Questions
Which varnish is used in oil-filled transformers?
A varnish resistant to hot transformer oil. Orchem OR 3xx baking varnishes provide this resistance.
Which class is needed for dry-type transformers?
Dry-type transformers running at high temperature usually need class H (180 °C) varnish. Choose by the class on the transformer's rating plate.
Do you also supply transformer exterior paint?
Yes. We supply transformer exterior paints as well as pole and insulating paints.