01 · Define the electrical duty
Specify rated capacity, primary and secondary voltage, frequency, vector group, impedance and tapping requirements. Confirm values with the engineer responsible for your project.
SOURCING GUIDE
Define the requirement.
Then compare the manufacturer.
A practical checklist for your transformer inquiry.
02 · Describe the installation
Include indoor or outdoor use, ambient conditions, altitude, space limits and cooling requirements. State the applicable project standards.
03 · Request model-specific evidence
Ask for the proposed model datasheet, guaranteed no-load and load losses, materials declaration, routine test scope and applicable type test reports. Do not treat a generic company certificate as evidence for a specific model.
04 · Compare the complete offer
Review technical compliance, exclusions, delivery, installation support and warranty terms. Resolve unknown specifications before making a procurement decision.
Applications shape the requirement
Utility grids, factories, commercial buildings, renewable energy projects and rail systems have different duties. Describe your actual operating conditions in the RFQ, rather than assuming a category label guarantees suitability.
Build a brief suppliers can respond to.
Use the same project brief for every shortlisted manufacturer. Ask suppliers to identify the exact proposed model and distinguish guaranteed values from catalogue ranges or optional configurations.
| Include in the RFQ | What to clarify | What to request back |
|---|---|---|
| Electrical rating | Rated capacity, primary and secondary voltage, frequency and connection requirements. | An identified model and datasheet matching the proposed duty. |
| Operating conditions | Load profile, ambient conditions, altitude, installation space and cooling requirements. | Design assumptions, limitations and any excluded operating conditions. |
| Loss guarantees | No-load and load losses with the rating, test method and relevant reference conditions. | Guaranteed values for the offered model, supported by applicable documentation. |
| Impedance | The impedance requirement specified by the project engineer and its reference conditions. | The offered value and the conditions under which it is specified. |
| Materials | Winding and core requirements and any project restrictions on insulating materials. | A clear material declaration that applies to the offered model. |
| Evidence | Required routine or type-test documents and the scope required by the project. | Report identity, issuing organisation, date, model coverage and any limitations. |
| Commercial scope | Quantity, destination, delivery requirements, installation and support responsibilities. | A quotation identifying inclusions, exclusions, delivery assumptions and warranty terms. |
Read the directory’s evidence labels correctly.
Manufacturer-published identifies the source of a statement. Source-reviewed means the platform has checked the referenced public material. Neither label means an independent test laboratory has verified the offered unit.
Not documented means the relevant value or evidence is unavailable in the record. It is not zero and does not prove the manufacturer cannot supply the requirement. Technical filters exclude unknown values when they cannot support the selected condition.
Resolve these gaps before comparing prices.
- A supplier gives a series capacity range without identifying the offered model.
- Loss figures refer to different ratings or omit necessary reference conditions.
- A test report covers a different model or does not show its scope.
- A material claim has no clear connection to the offered configuration.
- Transport, installation, testing or support responsibilities remain unclear.
Record each unresolved point in the manufacturer’s separate conversation. Final technical selection and project compliance should be reviewed by the responsible engineer.