What we buy
Ranges we buy on this page
A dual-voltage transformer has two primary or two secondary voltages selectable by tap or winding connection. This page covers identification, testing, removal, and purchase assessment for plant engineers, utility asset managers, facility directors, contractors, and trustees handling these units in North Carolina.
| Phase | kVA | Voltage | Fluid |
|---|---|---|---|
| 1 or 3-phase | 25 - 20,000 kVA | Dual-Voltage Transformers | Liquid or dry |
| 3-phase | 75 - 10,000 kVA | up to 34.5 kV | Liquid-filled |
Who we buy from
Six kinds of seller
- Recyclers
- Electrical contractors
- Equipment dealers
- End users
- Demo contractors
- Distributors
Fast offers
A written offer the same business day, based on your photographs.
Dedicated logistics
Our own crew, trailer and crane, not a brokered haul.
No broker fees
One buyer from first call to cleared pad, with nothing skimmed.
How it works
Six steps from photograph to payment
- 01
Take pictures
Photograph the nameplate, the inside of the cabinet and the tank from both ends. Four frames on a phone are enough to price most units.
- 02
Send them to us
Email or text the photographs with the site address and whether the unit is still energised. We reply the same business day with questions or a number.
- 03
Review the offer
The offer names the unit, the site, the price and the pickup window. It is written, dated and good for thirty days unless the unit changes hands.
- 04
We schedule freight
A crew, a trailer and a crane if the pad needs one. You get the date and the arrival window, and the site does not have to close for it.
- 05
Testing on arrival
Winding resistance, insulation resistance and a turns ratio check, plus oil analysis where the unit is liquid-filled. Results travel with the unit.
- 06
Get paid
Payment is released against the signed bill of sale and the scale ticket, by check or ACH, with the paperwork copy left on site.
What we handle
The parts sellers dread
Rigging
Crane, skates and a route survey for anything that will not roll onto a trailer.
Oil containment
Pans, absorbent and a spill plan before a drain plug is touched.
Bill of sale
A document that clears a lien, a lease or a bankruptcy file, not a handwritten note.
PCB paperwork
Testing and manifesting for pre-1979 oil, handled before the unit moves.
On the ground
What Dual-Voltage Transformers means
Dual-voltage construction allows a transformer to operate at either of two specified primary voltages or two specified secondary voltages. The nameplate connection diagram identifies the permitted arrangement.
A 2,400/4,800-volt primary, for example, may use series-parallel winding connections rather than an ordinary adjustment tap used to correct incoming voltage.
Insulation and clearance requirements follow the higher voltage class. The lower class is a connection, not a separate insulation rating.
Bushings, internal leads, and winding insulation must suit the higher-class design; reconnecting for the lower voltage does not authorize reduced electrical clearances or establish a different BIL.
Local reality
North Carolina installations
North Carolina plants sometimes changed utility service without replacing their transformer. A mill near Gastonia or a manufacturing campus in the Piedmont may retain a dual-primary unit through that change.
The useful evidence is the original nameplate, the utility service drawing, and the documented reconnection date.
At a former textile plant, the present feeder voltage may differ from the voltage shown on an old one-line diagram. Record both selectable voltages and the actual connection before describing the transformer.
Duke Energy service records, where applicable, can help resolve the service history but cannot establish internal jumper positions.
Around the site
Clearances that decide the rigging
A dual-voltage tank may fit its concrete pad while its higher-class bushings dictate a taller lift envelope. Measure overall height, radiator projection, and clearance beneath overhead conductors.
The selected lower-voltage connection does not make those bushings shorter or eliminate the need to confirm isolation of nearby energized equipment.
Inside a North Carolina plant substation, a fence gate or overhead bus can control the removal route more than tank width. Record the opening, crane position, and lifting-lug locations.
If bushings or radiators must come off, document their orientation and protect exposed lead openings against moisture during staging.
Where it sits
Field testing
Transformer turns-ratio testing should match the selected connection and the nameplate diagram. A result evaluated against the wrong primary voltage can suggest a winding problem that is actually a documentation error.
Qualified personnel should verify selector position or jumper arrangement before interpreting ratio, phase relationship, and winding-resistance results.
For an oil-filled dual-voltage unit, include available dissolved-gas results, dielectric test records, and evidence of leaks around selector shafts or cover gaskets. An overheating jumper or damaged connection board can affect one arrangement differently from another.
Failed equipment remains relevant for purchase assessment, but the failure description must distinguish observations from assumptions.
On the ground
Moving high-voltage equipment
Before removal, qualified crews must isolate every source, verify absence of voltage, and apply grounding under the site's electrical safety procedure. A selectable secondary can still receive backfeed from connected equipment.
Capture the dual-voltage connection diagram before cables, elbows, or internal links are disturbed during disconnection and dismantling.
Lowboy selection depends on documented transport weight and loaded height, including higher-class bushings left in place. Use designated lifting points and an appropriate spreader bar rather than treating radiator brackets as rigging attachments.
For North Carolina highway moves, the carrier should evaluate permits and route restrictions against the actual transport configuration.
Local reality
Valuation notes
Purchase assessment starts with the two selectable voltages, kVA, phase, frequency, and connection method. A legible diagram matters more than a description such as convertible primary.
Missing links, a seized selector, or an undocumented field conversion can prevent confirmation that both nameplate arrangements remain usable without repair or further investigation.
For retired North Carolina plant equipment, include ownership documentation, fluid identification, PCB records where applicable, and the reason for removal. Copper or aluminum winding information should come from records rather than appearance.
Dual-voltage capability does not establish condition; a burned winding or cracked bushing still needs a clear description.
Around the site
Next steps
Photograph the complete nameplate, connection diagram, selector handle, bushings, and all sides of the tank. Include the present primary and secondary voltages, available test reports, and any service-change paperwork.
Do not open an energized compartment to obtain a photograph or move a selector just to demonstrate its travel.
Transformer Buyers NC buys dual-voltage units throughout North Carolina, including equipment removed after a utility service change. Provide the site address, access restrictions, estimated dimensions, and whether the transformer remains connected.
Identify who controls release of the equipment and whether the original dual-voltage links or selector parts accompany it.
Get started
Get an offer in minutes
Five fields is all it takes. Photographs help, but a nameplate and a town are enough to start.
No fee, no obligation. We reply the same business day.
Tell us what you have
We reply the same business day.
Questions
Straight answers
Equipment types
Are ordinary voltage taps the same as dual voltage?
Not necessarily. Ordinary adjustment taps compensate for supply variation around a nominal voltage. A dual-voltage nameplate specifies two operating voltages and their permitted connections. Check the diagram rather than assuming that a five-position tap switch makes a transformer dual-voltage.
Service area
Can the voltage connection be changed while energized?
Do not assume it can. Series-parallel links and de-energized selectors require isolation before operation. Only equipment expressly designed and documented for energized switching permits that function under its specified conditions. The dual-voltage designation alone does not establish switching capability or a safe operating procedure.
Payment
What records help identify a reconnected plant transformer?
Provide the nameplate diagram, current one-line, utility service-change documents, and any reconnection or commissioning report.
Logistics
Field testing: what should a seller know?
Transformer turns-ratio testing should match the selected connection and the nameplate diagram. A result evaluated against the wrong primary voltage can suggest a winding problem that is actually a documentation error.