Our supply
Core focus
Products
Liquid-immersed power and distribution transformers
New-manufacture units up to 50 MVA, designed for 60 Hz service and built to the IEEE C57 series. Every unit is routine tested per IEEE C57.12.90 and delivered with test certificates issued against its serial number.
Interactive
Anatomy of the unit
Select a numbered point to see what it is and how it is specified. Diagram is a schematic elevation, not a drawing of a specific unit.
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Select a point
Nine points on the unit
Tap or click any numbered marker on the diagram to see what that component is and how it gets specified on an order.
Tap a marker on the diagram, use the buttons below, or tab to a marker and press Enter.
Expansion tank that keeps the core and windings covered with insulating liquid as the oil volume changes with load and ambient temperature. Fitted with a dehydrating breather so the oil is not exposed to moist air.
Specified as part of the accessory scope at quotation.
Insulated terminations that carry the primary conductors through the tank wall. The voltage class determines the creepage distance and therefore the physical size of the bushing.
Primary voltage class is confirmed against your specification before quotation.
Secondary terminations. Shorter than the HV bushings because the insulation requirement is lower, and usually carrying substantially higher current.
Secondary voltage class and current rating confirmed at quotation.
Stacked laminations of grain-oriented electrical steel forming the magnetic circuit. The core is the dominant contributor to no-load loss, which is present whenever the unit is energised regardless of load.
Core design is fixed for 60 Hz at the design stage. A 50 Hz core is not modified to run at 60 Hz — it is a different design.
High- and low-voltage windings arranged concentrically around each core limb. The windings dominate load loss, which varies with the square of the load current, and they set the impedance.
Both no-load and load loss are guaranteed values in our quotations, backed by liquidated-damages language and verified by the routine test on your unit.
Sealed steel enclosure holding the core, windings and insulating liquid. Leak and pressure testing of the tank forms part of the routine test sequence.
Metal-enclosed and substation-type construction per IEEE C57.12.10.
Detachable cooling panels that dissipate heat from the insulating liquid. The cooling class determines whether circulation is natural or assisted by fans or pumps, and therefore what continuous rating the unit will carry.
Cooling class and any overload duty are confirmed against your specification.
Houses the tap-changing mechanism. A de-energised tap changer is operated with the unit off supply; an on-load tap changer adjusts under load. Which one applies, and the tap range and step size, follow your specification.
Tap arrangement is one of the items we ask for in an enquiry.
Records rating, voltage class, impedance, frequency, cooling class, liquid volume and the unit's serial number.
The serial number is the link between the physical unit and its routine test certificate — which is why we issue certificates per serial number rather than per order.
Specification summary
Supply scope
| Product | New-manufacture liquid-immersed power and distribution transformers |
|---|---|
| Rating range | Up to 50 MVA. Core commercial focus is the 12–50 MVA class. |
| Design standards | IEEE C57.12.00 — general requirements for liquid-immersed distribution, power and regulating transformers IEEE C57.12.10 — metal-enclosed / substation transformers |
| Test standard | IEEE C57.12.90 — test code for liquid-immersed transformers |
| Routine tests | Performed on every unit; certificates issued per serial number |
| Factory acceptance | Witnessed by an independent third-party inspection agency; customer or customer-appointed inspector welcome |
| Loss performance | Guaranteed no-load and load loss values, quoted with liquidated-damages language |
| Frequency | 60 Hz |
| Typical lead time | Approximately 8 months from order release |
| Delivery terms | DDP to site is quotable. Other Incoterms 2020 arrangements can be quoted on request. |
Interactive
Loss-evaluation calculator
Municipal utilities and cooperatives rarely award on first cost. Losses are capitalised over the life of the unit and added to the purchase price to give an evaluated cost. Enter your own figures and rates below.
Total ownership cost
Evaluated cost calculator
Illustrative figures only. These are arbitrary numbers for demonstrating the arithmetic. They are not an AxionOrbital quotation and not representative of any unit.
$
Leave blank to see the capitalised loss value on its own.
W
W
$/W
$/W
Rates default to the values published by ElectriCities of North Carolina in its own bid documents — a widely used public example of the practice. Replace them with the rates your own procurement applies.
Evaluated cost
—
Enter loss figures to evaluate.
Purchase price
No-load loss
Load loss
Formula: evaluated cost = purchase price + (no-load loss W × $/W) + (load loss W × $/W).
Attributed to ElectriCities of North Carolina as a published example of standard
loss-evaluation practice; it is not our methodology, and the capitalisation rates applied to
your procurement are yours to set. This tool performs arithmetic on figures you enter and
does not transmit them anywhere.
We quote guaranteed no-load and load loss values, with liquidated-damages backing, precisely so they can be entered into a formula of this kind as firm numbers. A supplier who will not guarantee losses cannot be evaluated on this basis, and on a loss-evaluated bid that is usually decisive.
Interactive
Where does your rating land?
Rating drives three separate things at once: whether we can supply it, which tariff subheading it falls under, and whether DOE efficiency rules apply. Drag to see all three.
Rating & classification
15 MVA
110255055 MVA
HTS subheading
8504.23
Section 232 duty
15%
DOE 10 CFR 431
Out of scope
Classification boundaries are 10,000 kVA for the HTS subheading and 2,500 kVA for DOE
scope. Duty rates change and classification is confirmed per order with our customs
broker — see Trade & Compliance.
Scope
Configuration is quoted against your specification
We do not publish a fixed catalogue. Rating, voltage class, impedance, cooling class, tap arrangement, bushing and accessory scope, and enclosure requirements are confirmed against the purchaser's specification at the time of quotation, together with the applicable standard revision.
If you are working to a utility standard specification, send it with the enquiry. We will respond with a clause-by-clause confirmation of compliance and an explicit list of any exceptions rather than a blanket statement of conformity.
What to include in an enquiry
- Rating (MVA) and voltage class, primary and secondary
- Impedance requirement and tolerance
- Cooling class and any loading or overload duty
- Tap arrangement — de-energised or on-load, range and steps
- Quantity, delivery location and required on-site date
- Governing standard specification, if you have one
- Whether the project carries domestic-content requirements — see Trade & Compliance
Technical notes
Points that come up regularly
Real engineering questions we get asked, answered without hedging.
Units intended for US service are designed for 60 Hz from the outset — a different core design, not a modified 50 Hz core. Frequency is fixed at the design stage and is stated on the test certificate and nameplate.
The Department of Energy efficiency standards at 10 CFR Part 431 apply to distribution transformers rated at or below 2,500 kVA. Power-class units above that threshold fall outside that scope.
We confirm which side of the line a given unit sits on as part of the quotation, because it changes both the applicable requirement and the documentation.
IEEE C57.12.90 routine tests are performed per unit. Type tests are performed per design. Special tests are performed when specified.
We supply routine tests on every unit as standard; type and special tests are available on request and are identified separately in the quotation so there is no ambiguity about what is included. Details are set out under Quality & Testing.
Factory acceptance testing is witnessed by an independent third-party inspection agency, and you or an inspector you appoint are welcome to attend. We will schedule the test to accommodate attendance and give reasonable notice of the date.
Transformers we supply are of foreign manufacture. They are not compliant with Buy America, Build America Buy America, RUS domestic-content rules or comparable state requirements. If your project carries any domestic-content condition, tell us at enquiry stage and we will decline rather than waste your evaluation time.
Request a quotation
Send your specification and required dates. You will get confirmation of what we can quote today, the current lead time, and any exceptions to your specification.