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Step Up and Step Down Transformers Explained
A transformer does not care which way power flows through it. Step up and step down describe how it is being used, not usually how it is built.
| Step up | Step down | |
|---|---|---|
| What it does | Raises voltage, lowers current | Lowers voltage, raises current |
| Turns ratio | Secondary has more turns than primary | Primary has more turns than secondary |
| Where used | At generation, to push power long distances | At the customer end, to make it usable |
| On a pad-mount | Rare, and only on generation or solar sites | This is the normal case, 12470 down to 480 |
| Reversible | Many units can be reverse fed with care | Same unit, fed the other way |
Which you actually need
A three phase pad-mounted distribution transformer is a step down unit in almost every installation, taking utility primary at 12470 or 13200 volts down to a usable 480Y/277 or 208Y/120. Reverse feeding a step down unit to step up is possible but it changes the impedance seen by the system and voids some warranties, so check with the manufacturer rather than assuming.
Working from a specification that uses one of these terms loosely? Send it over and we will tell you which equipment it is actually calling for, before you order the wrong thing. Get a quote or call 786 220 2801.