What is a transformer nameplate?
The nameplate is the transformer’s identity and rating in one place: the power it can supply, the series current it is built for, its frequency and insulation class, and the marks that trace it. Read it before you select, test or replace a unit.
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Select a field on the plate, or use the buttons below, to see what it tells you and why it matters.
The transformer nameplate is the permanent marking on a series isolation transformer that says what it is and what it is rated for. It normally carries the maker and model, the power rating, the primary and secondary current, the frequency, an insulation rating for the primary circuit, and a serial or batch mark for traceability.
Read it before you select, test or replace a transformer. The current marking has to match the circuit the CCR supplies, and the power rating has to cover the fitting it feeds. The plate gives power and current rather than a fixed voltage, because with a constant loop current the voltage follows the load. Wording and layout differ between manufacturers, so confirm against the data sheet and the design drawings. A readable plate never makes the leads safe to touch: isolate and make the circuit safe under site procedures before any work.
Frequently Asked Questions
Q1What is a transformer nameplate in AGL?
The label, plate or permanent marking on a series isolation transformer that states what it is and what it is rated for: manufacturer, model, power rating, primary and secondary current, frequency, insulation class and a serial or batch mark. It is the first thing to read before fitting, testing or replacing a transformer.
Q2Why does the nameplate show a current ratio like 6.6 A : 6.6 A?
A series isolation transformer is built to pass the circuit current from primary to secondary. The ratio tells you the primary current it is designed for and the current it delivers to the fitting. It must match the circuit current the CCR supplies, otherwise the lamp or LED driver is under- or over-driven.
Q3What does the power rating on the nameplate mean?
It is the maximum load the transformer is designed to supply at its rated current, in watts or volt-amperes. The connected fitting should not exceed it. A 45 W fitting on a transformer rated below 45 W (for example a 30 W-only unit) would overload it and shorten its life, whereas a 30/45 W dual-rated unit carries it at its upper rating; a larger rating than needed is generally acceptable within the design limits, but it adds to the loop load and lowers the power factor, so match the rating to the fitting.
Q4Does the nameplate give the transformer’s voltage?
Not as a single fixed figure. Because the loop current is constant, the secondary voltage follows the load, roughly power divided by current. The plate normally gives power and current ratings instead, plus an insulation rating that covers the high voltage of the primary circuit.
Q5What should I do if the nameplate is missing or unreadable?
Do not guess the rating. Identify the transformer from the installation records, the design drawings or the batch and serial mark if one survives, and confirm it against the manufacturer’s data. If it cannot be confirmed, treat it as unidentified and replace it with a known, correctly rated unit under site procedures.
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