Any condition, any size
Harmonics and Transformer Derating
A working guide for Ohio sellers: what decides the number and how the unit leaves.
What we buy
What we buy here
Harmonics and Transformer Derating is one of those subjects where the wrong assumption is expensive and the right one takes ten minutes. A unit that came out of a working plant is almost always the better buy, and sellers rarely realise it. A short drive within one county costs less than a long drive across three, and the number shows it.
Do the cheap checks first, because they eliminate most of the expensive possibilities. The unit is the easy part; the site, the access and the paperwork are where the time goes. A desk that buys for its own account answers with a figure rather than a promise to find one.
Who we buy from
Six kinds of seller, one desk
- Recyclers
- Electrical contractors
- Equipment dealers
- End users
- Demo contractors
- Distributors
Fast offers
A nameplate photo is usually enough to price a unit the same day.
Dedicated logistics
We arrange the crane, the permits and the flatbed, not you.
No broker fees
You are dealing with the buyer, so nothing is shaved off the offer.
How it works
Six steps from your yard to the money
- 01
Take pictures
The nameplate, the cabinet interior and the tank in daylight. Three photographs are usually enough to place a unit in the right class and the right price band.
- 02
Send them to us
The form on this page, a text or an email all reach the same desk. Include the city, the access and any deadline the site is working to.
- 03
Review the offer
A buyer reads the photographs, asks one or two questions and sends a written offer with the assumptions stated, so nothing changes on the day.
- 04
We schedule freight
Crane, flatbed and permits are booked around your access. You get a date and a window, and we carry the cost of getting it right.
- 05
Testing on arrival
Winding resistance, megger and turns ratio, plus oil analysis where the unit is liquid filled. The results decide the final number, and you see them.
- 06
Get paid
Payment is released on the agreed terms once the unit is received and tested, by check or ACH. No retention, no sixty-day terms.
What we handle for you
The parts sellers dread, done for you
Rigging
Crane and forklift arranged around your access, not the other way round.
Oil containment
Bunds, absorbent and disposal handled before the unit moves.
Bill of sale
A clean title document for your records, signed on collection.
PCB paperwork
Pre-1979 units get the testing and the manifest they need.
Guide
Where harmonics come from
Switch-mode power supplies, variable frequency drives, LED drivers and anything with a rectifier front end produce harmonic current. Triplen harmonics add in the neutral rather than cancelling, which is why a neutral sized for the fundamental is too small. Harmonic current also produces eddy losses in the core and the windings, which show up as heat.
A mine-duty unit is designed to be dragged, and it looks it, which is not the same as being worn out. A transformer with its original documentation is easier to insure, easier to resell and easier to explain.
What happens to the transformer
A standard unit running a harmonic-rich load will exceed its temperature rise at less than nameplate current. The derating factor depends on the harmonic spectrum, which is why a K-rating exists as a shorthand. Overheating from harmonics degrades insulation from the inside, and the oil test usually shows it late.
A site manager who has already cleared the pad has done most of the work that matters. A buyer who works the whole state can move a unit to whichever plant needs it, which is why the coverage matters.
What to do about it
Specify a K-rated unit, oversize a standard unit, or filter the harmonics at the source. Oversizing is the simplest answer and often the cheapest, because a larger standard unit runs cooler. Filtering is the most effective answer when the load is concentrated in one drive system.
A hot mechanical room quietly derates everything in it, and nobody notices until a unit fails early. A transformer is a boring asset until the day it fails, and then it is the only thing anyone discusses.
At purchase
Checklist for harmonics and transformer derating
Questions about harmonics and transformer derating
Related guides
Get started
Get an offer in minutes
Five fields and a phone number is all we need to start. We reply the same business day, and a firm number follows the nameplate photo.
(614) 715-3047or send the form and we will call you.
Questions
What sellers ask before they call
Equipment types
Does harmonics and transformer derating change what a transformer is worth?
Specify a K-rated unit, oversize a standard unit, or filter the harmonics at the source. Filtering is the most effective answer when the load is concentrated in one drive system.
Service area
Where does a seller start with harmonics and transformer derating?
Triplen harmonics add in the neutral rather than cancelling, which is why a neutral sized for the fundamental is too small. A seller with a deadline should say so early, because the schedule is built around the date rather than the unit.
Payment
Is harmonics and transformer derating part of what a buyer checks on site?
A used K-rated unit holds its value in any building with dense electronics. A used standard unit can still serve a harmonic-rich load if it is oversized enough, and the arithmetic is worth doing before rejecting it.
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