Resources
Buying a used or surplus power transformer: what to check
A surplus unit can save years, but only if it is what the seller says it is. Check these five areas before you commit.
Ownership
[PLACEHOLDER] Replace with final copy. Title, bill of sale, authority to sell and lien search.
Nameplate
[PLACEHOLDER] Replace with final copy. Photographs, serial number confirmed with the manufacturer, design drawings.
Dissolved gas analysis (DGA)
[PLACEHOLDER] Replace with final copy. Oil quality history and what DGA results indicate.
Field tests
[PLACEHOLDER] Replace with final copy.
- Power factor
- Winding resistance
- Turns ratio
- Sweep frequency response analysis (SFRA)
Storage history
[PLACEHOLDER] Replace with final copy. Storage logs, nitrogen pressure records and impact recorder data.