Transformer guides

What separates a step up from a step down transformer, whether one can be reversed, and the voltage combinations people actually ask for.

What a distribution transformer is, how it differs from a power transformer, the ratings it comes in and what one costs to buy today.

How three phase transformers work, how they differ from single phase, and the voltage and amperage questions that come up on every job.

What sits inside an electrical substation, how a substation transformer differs from a pad mounted unit, and where unit substations and switchgear fit.

The real trade off between dry type and liquid filled transformers, including cost, efficiency, life expectancy, indoor use and the fire code question.

Delta and wye connections explained, what L1, L2 and L3 mean, which connection is used where, and how to tell what a transformer is from its nameplate.

What goes into installing a pad mounted transformer, the pad itself, clearances, grounding, and the approvals that hold jobs up.

What pad mounted transformer lead times actually are right now, measured from real quotes, why they got long, and what shortens them.

What the DOE 2016 efficiency rule requires, what changes in 2029, and why a 2550 kVA transformer is exempt when a 2500 kVA one is not.

What causes distribution transformer failure, which tests find it, and what you can and cannot check with a multimeter.

What transformer each of these applications actually needs, why they differ from ordinary commercial loads, and what to specify.

Every field on a distribution transformer nameplate, what it means, and which ones decide whether a replacement will actually work.

What 11kV, 415V and 400V mean, why they never appear on a US job, and the North American ratings that correspond to them.

The honest answer to how many types of transformer exist, why every source gives a different number, and the classifications that actually matter when buying.

Whether 220 volts and 240 volts are the same thing, where each number came from, and when the difference actually matters.

What MVA means on a transformer, a kVA to MVA conversion table with full load amps, and where the equipment stops being a pad mount and becomes substation plant.

What 1 phase 2 wire and 1 phase 3 wire mean, why split phase is not two phase, and which one a service actually has.

Which side to energise, what happens if you wire one backwards, how to size the primary conductors, and the checks before you close the switch.

How much copper and aluminium is actually in a transformer, what a decommissioned unit is worth as scrap, and the reason you cannot simply weigh it.

What a mobile substation is, when a trailer mounted transformer beats a permanent build, and what a temporary power quote has to include.

Where surplus transformers come from, what to test before you pay, what to avoid outright, and when a remanufactured unit beats waiting for new.

Why most grounded wye to grounded wye pad mounted transformers use a five legged core, when a three limb core is perfectly acceptable, and the one question to ask a factory before you order.

What a UL file number under category XPLH is, how it differs from a certificate number, and how to check that a pad mounted transformer is genuinely listed before you order.

How many amps a well pump draws at 115, 230 and 460 volts, the largest breaker and smallest wire for each horsepower, how far each wire size can run, and when a pump needs a transformer.

How much electricity data centers use, by facility size, per rack and per year, with the US and world totals, where the power goes, AI racks against traditional ones, and the transformers a 10, 50 or 100 MW site needs.

What MW means for a data center, how critical IT load differs from total facility power, what a megawatt costs to build, and the racks, transformers and generators in 5, 20 and 100 MW sites.

What a small transformer is worth as scrap, typical weights for control, toroidal and dry type units, how to tell copper from aluminum windings, and why yards pay a whole unit price.