What we buy
Ranges we buy on this page
Transformer Buyers NC buys used, surplus, failed and obsolete drive isolation transformers throughout North Carolina. This page covers units built to sit between a variable-frequency drive and the motor it controls, including equipment removed from pump stations, paper mills and HVAC plants.
For plant engineers, water utility managers and demolition crews, the important records are the nameplate, drive specifications, insulation test results and removal plan. Those details establish what the unit actually handled.
| Phase | kVA | Voltage | Fluid |
|---|---|---|---|
| 3-phase | 5 - 1,000 kVA | 5 kV | Dry-type |
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
Drive Isolation Transformers explained
A drive isolation transformer in this application sits on the output side of a variable-frequency drive, between the drive and its motor. Its winding design must accommodate the actual output waveform.
A standard line-frequency transformer should not be assumed suitable just because its voltage and kVA markings match the motor circuit.
The term drive isolation also appears on transformers installed ahead of drives. Photographs of cable connections and a one-line diagram help separate those arrangements.
For an output-side unit, record the drive model, motor voltage, operating frequency range and switching settings rather than relying on a faded drive-duty label alone.
Local reality
The North Carolina install base
North Carolina paper mills use variable-speed equipment on pumps, fans and conveyors, where a drive isolation transformer may remain after the associated production line shuts down. Mill records should identify the driven machine and its operating duty.
A conveyor that ran intermittently presents a different thermal history from a continuously loaded pump.
Water plants, large pump stations and HVAC plants can retain these units through several drive replacements. In a municipal pump room, trace the circuit to the motor before assigning an equipment description.
Facility directors should preserve drive replacement records, because changed switching settings can matter even when the transformer itself never moved.
Around the site
The inspection that decides value
Inspection starts with winding shielding, insulation condition and evidence of harmonic heating. Darkened varnish, brittle lead insulation and heat discoloration near winding connections deserve close attention. Drive-duty units run hot, and their insulation is usually the first thing to fail.
A clean enclosure does not establish that the winding survived service.
Core saturation requires review of the applied voltage and operating frequency, not simply a visual check of the laminations. We also review the kVA rating against the manufacturer's limits at the drive's carrier frequency.
Insulation resistance results, temperature records and fault reports help explain whether damage developed gradually or followed one event.
Where it sits
Fluid condition and PCB status
Many drive isolation transformers are dry-type units, so fluid sampling does not apply to every removal. Confirm the construction from the nameplate and enclosure before requesting oil records.
For a dry-type unit, winding contamination, cooling passages and insulation test history are more relevant than a fluid report from nearby electrical equipment.
If the drive isolation unit is liquid-filled, identify the insulating fluid and retain any laboratory results documenting PCB status. An unreadable label or an old tank cannot establish that status.
Note leaks at gaskets, drain valves and bushings, and keep sampling records tied to the transformer's serial number throughout removal and transport.
On the ground
Getting it off the pad
Before a drive isolation transformer leaves its pad or equipment room, qualified personnel must isolate the circuit and verify absence of voltage. The drive's DC bus can retain charge after incoming power is disconnected.
Follow the drive manufacturer's discharge procedure, and identify motor-side conductors before anyone opens the transformer connection compartment.
Removal planning needs the actual weight, lifting instructions and a clear route past the drive cabinets. Do not lift a dry-type assembly by its ventilation panels or winding supports.
Document doorway dimensions, pad access and loading conditions; use a spreader bar or other rigging only as the manufacturer's lifting arrangement requires.
Local reality
What a buyer weighs up
A buyer reviews the drive isolation transformer's identity, condition and documented duty together. The nameplate should show kVA, primary and secondary voltages, phase and frequency information.
Manufacturer drawings are particularly useful when the winding shielding or output-side application is not evident from the plate. Missing records leave important technical questions unresolved.
Failed units need a clear account of the failure: winding short, insulation breakdown, overheating or damage during a drive fault. Surplus units need their storage history instead.
In a paper mill laydown area, rain through damaged louvers can change insulation condition even if the transformer operated normally before the line was dismantled.
Around the site
The next step for a drive isolation
Prepare photographs of the complete drive isolation transformer, its nameplate, terminals and any damaged winding insulation. Include the North Carolina site location and whether the unit remains connected to its drive.
A one-line diagram and drive model number help establish whether the transformer served the input circuit or the motor-side circuit.
Transformer Buyers NC buys drive isolation transformers from operating facilities, closed plants and equipment removal projects across the state. For a disconnected pump-station unit, the useful package includes test reports, fluid documentation when applicable, weight and loading access.
Keep those records with the serial number so the inspection and pickup concern the same equipment.
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
Can you buy a failed drive isolation transformer?
We buy failed drive isolation transformers in North Carolina. Describe the fault and include photographs of burned leads, winding damage or enclosure discoloration. Retain insulation test results and the drive fault log if available. Do not energize a damaged unit to demonstrate its condition.
Service area
Which drive records help identify the transformer duty?
The drive model, carrier frequency setting, motor voltage and one-line diagram help identify the application. Include manufacturer instructions for the transformer if available. Output-side duty cannot be established from kVA alone, especially after a pump station or mill has replaced its original drive.
Payment
Does every drive isolation transformer need PCB testing?
A dry-type drive isolation transformer has no insulating fluid to sample. For a liquid-filled unit, retain documentation identifying the fluid and its PCB status, and determine any testing needs before handling.
Logistics
Getting it off the pad: what should a seller know?
Before a drive isolation transformer leaves its pad or equipment room, qualified personnel must isolate the circuit and verify absence of voltage. The drive's DC bus can retain charge after incoming power is disconnected.