What we buy
Ranges we buy on this page
This guide explains transformer temperature rise, including the 55, 65 and 80°C classes, and how hotter windings shorten insulation life. It is written for North Carolina plant engineers, utility asset managers, facility directors and crews preparing equipment for removal.
| Phase | kVA | Voltage | Fluid |
|---|---|---|---|
| 1-phase | 10 - 333 kVA | up to 25 kV | Liquid or dry |
| 3-phase | 75 - 20,000 kVA | 46 kV | Liquid or dry |
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 it is
Temperature rise is the increase in average winding temperature above the cooling medium under specified test conditions. On an air-cooled transformer, that reference is ambient air.
A 65°C rise marking does not mean the winding operates at an absolute temperature of 65°C inside the tank.
The nameplate rise rating normally comes from a temperature-rise test, with average winding temperature determined by resistance measurements. Local hot spots can run above that average.
Liquid-filled units also have top-liquid temperature limits, so a dial thermometer reading is not the same measurement as the winding rise.
Local reality
Why it matters when you sell
For an owner retiring a North Carolina plant transformer, the rise marking helps identify its thermal design, not its present condition. Transformer Buyers NC buys used, surplus, failed and obsolete transformers.
A readable nameplate and records of sustained overloads help separate an intact unit from one with heat-damaged insulation.
An outage report describing a stopped radiator fan carries more useful evidence than a statement that the transformer ran hot. Record the load, ambient temperature, cooling stage and alarm indication if known.
That context helps explain whether a high reading reflected overload, restricted cooling or an instrument fault.
Around the site
The numbers
A 55°C or 65°C rise rating commonly appears on liquid-filled transformers; an 80°C rise rating commonly appears on dry-type equipment. These numbers describe permitted average winding rise under the applicable rating conditions.
They do not, by themselves, identify the insulation system, cooling arrangement or allowable hot-spot temperature.
For illustration, adding a 65°C average winding rise to 30°C ambient gives 95°C average winding temperature, not the hot spot. Some nameplates list dual 55/65°C ratings with different kVA capacities.
Use the matching capacity and cooling designation rather than treating both temperature markings as interchangeable operating limits.
Where it sits
Common mistakes
Do not confuse winding rise with insulation thermal class. An 80°C-rise dry-type transformer may use a substantially higher thermal-class insulation system. The rise marking alone cannot establish its temperature ceiling.
Photograph the complete nameplate, including insulation class, kVA, voltage and cooling information, before drawing conclusions about thermal margin.
Another mistake is treating a clean enclosure as proof of healthy windings. Blocked dry-type ventilation passages, dust on coils, closed radiator valves or failed fans can raise internal temperatures without obvious exterior damage.
A burned terminal may instead indicate a loose connection; its location matters when describing the failure.
On the ground
How it affects value
A lower rise rating is not automatically evidence of better remaining condition. A 55°C-rise transformer subjected to prolonged overload can have more insulation deterioration than a properly operated 65°C-rise unit.
For acquisition assessment, the useful distinction is documented thermal exposure alongside electrical tests, oil condition and physical damage.
Heat accelerates insulation aging, particularly in liquid-filled transformers where moisture and oxygen also affect paper deterioration. There is no universal remaining-life calculation from the rise marking alone.
Oil test reports, dissolved gas trends and evidence of brittle paper can change whether equipment is assessed for continued service or material recovery.
Local reality
What to do next
Build a temperature-rise record before the transformer leaves its North Carolina site. Include the nameplate photograph, serial number, rated kVA, cooling code and any separate 55/65°C capacities.
Attach available temperature logs, fan maintenance records and test reports, clearly identifying which readings represent top oil rather than winding temperature.
Leave testing and isolation to qualified personnel. Do not energize a failed transformer merely to obtain a temperature reading, and do not open the tank to inspect paper without an approved procedure.
For removal planning, identify disconnected cables, leaking gaskets and attached radiators separately from the thermal condition record.
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
Does 65°C rise mean a 65°C winding temperature?
No. The rise is measured above the reference cooling-medium temperature under specified conditions. At 30°C ambient, a 65°C average winding rise corresponds to 95°C average winding temperature. The winding hot spot can be higher, and a top-oil thermometer measures something different.
Service area
Is an 80°C-rise transformer necessarily running too hot?
No. An 80°C rise can be a normal nameplate rating for dry-type equipment. Assess it against its insulation system, load and specified operating conditions. Blocked coil ventilation or a failed enclosure fan still warrants investigation, even when the nameplate permits that rise.
Payment
Can temperature rise reveal remaining transformer insulation life?
The nameplate rise cannot reveal remaining life by itself. Actual winding temperature, exposure duration, moisture and insulation condition matter. For a liquid-filled unit, operating logs and oil test trends provide evidence of thermal stress, but they do not establish an exact retirement date.
Logistics
How it affects value: what should a seller know?
A lower rise rating is not automatically evidence of better remaining condition. A 55°C-rise transformer subjected to prolonged overload can have more insulation deterioration than a properly operated 65°C-rise unit.