Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

TOMI

Symbols

Transformer overexcitation measurement interface

Relates the transformer voltage and frequency inputs to its selected overexcitation supervision. Transformer monitoring interfaces connect physical sensors and protection calculations to the station's alarms and trip logic. Temperature, oil, gas, pressure and electrical measurements indicate different conditions and require separate interpretation.

Drawing use

Schematic

Application

Metering & protection

Reference family

Manufacturer

A distinction that matters

Allowed duty depends on transformer design. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.

Full referenceAdd to legend

TX

Symbols

Power transformer

A power-transformer representation identifies equipment transferring electrical power between winding circuits. The generic mark can show the relationship between windings, but voltage levels, winding connections, vector group, rating and earthing information require additional annotations and equipment references.

Drawing use

SLD / Schematic

Application

Power distribution

Reference family

IEC / IEEE / ANSI

A distinction that matters

A transformer used for voltage measurement is a VT or PT. Its function and secondary circuit differ from those of a power transformer.

Full referenceAdd to legend

Follow the full entry for source drawings and the appropriate standard or selected product. Equipment previews show a manufacturer drawing where available, otherwise a 3D thumbnail.