A used transformer's price is only part of the decision. Missing records or tests may create significant safety and cost exposure after installation.
This guide is general information. HV/MV intervention and testing must be carried out by qualified personnel under the equipment manual and facility safety procedures.
Nameplate and history
Confirm rated power, voltages, vector group, impedance, year and cooling type against the receiving facility. Request maintenance, fault, transport and storage records. An unreadable nameplate may call for additional verification.
- Power, voltage and vector group
- Leaks, corrosion and physical damage
- Maintenance and transport history
- Technical fit with the new installation
A suitable test package
Oil-filled and dry-type units require different physical checks. TTR, insulation and winding-resistance tests are selected by equipment type and condition. Compare findings with nameplate and historical values where available.
The purchase decision
Consider warranty terms, transport, installation, spare parts and commissioning cost as well as test results. Suspicious findings may justify conditional acceptance, further testing or rejecting the unit.
Include total commissioning cost in the decision
A used transformer's rating, voltage, vector group and impedance must suit the destination installation. Request storage, transport and fault history. Inspect bushings, connections and accessories where safe and appropriate. Oil-filled and dry-type assets require different checks. The cost of tests, possible repair, transport, installation and commissioning should be considered together, rather than comparing purchase prices alone.
Decision checklist
- Nameplate compatibility with the installation
- Maintenance, fault, storage and transport history
- Physical condition and type-specific tests
- Repair, transport and commissioning cost
Related service
Request technical support →Frequently asked questions
Is a used transformer safe to buy without test records?
The technical risk is greater. Appropriate tests and history should be reviewed before purchase.
Is the same checklist valid for oil and dry types?
Some electrical and nameplate checks overlap, but oil and cooling checks differ.
Is one acceptable test result enough to buy?
No. History, physical condition, several suitable measurements and total cost all matter.
