Datasheet and ratings
Identify the proposed model and the electrical ratings that the document must cover.
Request for your projectHEAKOR / Buyer knowledge
Transformer buying,
made clearer.
Practical transformer buying guides for the decisions before a purchase.
Prepare the specification, check document scope and compare proposals on the same basis.
Choose your next task
What are you working on?
01 ↗
Choose a product family
Compare the main transformer arrangements.
02 ↗Prepare your specification
Collect the electrical, site and supply requirements.
03 ↗Send a complete RFQ
Use a practical checklist before requesting prices.
04 ↗Check certificate scope
Match the certificate to the model and rating.
05 ↗Plan a replacement
Record the existing equipment and site constraints.
06 ↗Compare quotations
Check technical scope, documents and commercial terms.
Start here / Procurement essentials
A better enquiry makes a better starting point.
Bring the electrical ratings, site conditions, destination, quantity and required documents together before requesting a quotation.
Open the transformer RFQ checklist- 01Identify the equipment and application
- 02Define electrical and site requirements
- 03List documents and approval needs
- 04Clarify quantity, destination and timing
The guide library
Read. Check. Prepare.
Use these guides to prepare questions for your technical team and supplier. Project documents govern final selection.
27 Oct 2026
Dry-Type Transformer Temperature Rise vs Insulation Class
Compare dry-type transformer temperature rise with insulation class. Align the offered rating, site conditions, thermal guarantee and supporting evidence bef...
Read the guide
26 Oct 2026
Buchholz Relay Gas Sampling: Ground-Level Package Scope
Buchholz relay gas sampling at ground level calls for a reviewed accessory package. Use this EPC checklist to define the relay connection, tube, fittings, su...
Read the guide
26 Oct 2026
Dry-Type Transformer Winding Substitution: Approval Checks
Dry-type transformer winding substitution from copper to aluminum calls for a documented review of losses, physical fit, terminations and approval evidence. ...
Read the guide
26 Oct 2026
Transformer Winding Resistance: Factory vs Site Reports
Transformer winding resistance reports need a common temperature, tap and terminal basis before factory and site results can be compared. Use this EPC guide ...
Read the guide
25 Oct 2026
Transformer Oil Sampling Points: Procurement Guide
Transformer oil sampling points need more than a valve line item. Agree point identity, fluid source, access, connection details and laboratory-equipment res...
Read the guide
25 Oct 2026
Transformer Neutral Grounding: NGR Supply Scope
For transformer neutral grounding with an external resistor, agree the neutral-terminal details, supply boundaries and coordinated drawings before accepting ...
Read the guide
25 Oct 2026
Pad-Mounted Transformer Foundation Openings
Pad-mounted transformer foundation openings need a coordinated review of the proposed equipment, pad and conduit drawings. Identify the controlling revisions...
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25 Oct 2026
Transformer Dielectric Test Schedule: Winding and Terminal Coverage
A buyer’s guide to agreeing winding and terminal coverage in a liquid-immersed transformer dielectric test schedule, without confusing technical scope with w...
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25 Oct 2026
Transformer SFRA Baseline: Agree the Reference Before Shipping
A transformer SFRA baseline is useful only for its intended comparison. Agree the transformer condition, reference purpose, data handover and engineering rev...
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25 Oct 2026
Dry-Type Transformer Reverse Feeding: Is a Step-Up Offer Suitable?
Dry-type transformer reverse feeding needs more than matching nameplate voltages. Separate manufacturer-supported alternatives from unresolved substitutions ...
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22 Oct 2026
Oil-Immersed Transformers for Motor Loads: Define the Starting Duty
Oil-immersed transformer enquiries for motor loads need more than running-load kVA. Define the motor-start duty, supply conditions and voltage criteria so th...
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22 Oct 2026
Transformer Oil Containment: Agree the Civil Interface Before Order
Transformer oil containment requires a clear equipment-to-civil handover. Confirm oil inventory, drawings, site interfaces and named responsibilities before ...
Read the guideCompare quotations
Put the proposals
on the same basis.
A lower price is only comparable when the proposed equipment and supply scope match. Record differences and resolve them before ordering.
Equipment
Compare capacity, voltages, phase, frequency, impedance, cooling and installation requirements against the same specification.
Documents and testing
Identify the proposed model, drawings, required test reports and any mandatory approvals. Check what is included and excluded.
Commercial scope
Compare quantity, delivery term and named place, packaging, transport, lead time, payment and warranty in writing.
Project documents
The right document. For the right model.
Tell us which documents your project needs. Availability and applicable scope are confirmed for the proposed model and configuration.
Outline and connection drawings
State the installation, cable-entry and clearance requirements you need to check.
Request for your projectTest and approval documents
Name the required tests, standard or approval, and the model or configuration concerned.
Request for your projectRequest documents for your proposed configuration
Include the model or product type, capacity, voltages, frequency and destination. Ask for the report number, date and test scope so you can check that the documents match the proposed configuration. An individual report does not establish certification for every model or destination.
When reviewing a document, match the legal entity, model, rating, applicable scope and issue date to your proposed equipment.
Read the certificate-scope guideOpen the document centreYour project / next step
Good decisions start with clear requirements.
Send the details you have. We can start the conversation while the remaining requirements are being confirmed.
Discuss your project