Understand the difference.

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

ATS

Symbols

Automatic transfer switch

An automatic transfer switch monitors the normal supply and, when voltage or frequency goes out of limits, signals the generator to start and transfers the load to the alternate source once it is ready. When the normal supply returns and is stable, it transfers back after a time delay. Most units use an open-transition break-before-make sequence.

Drawing use

SLD / Schematic

Application

Microgrid systems

Reference family

IEC / IEEE / ANSI

A distinction that matters

An automatic transfer switch operates without an operator; a manual transfer switch needs someone to move it.

Full referenceAdd to legend

MTS

Symbols

Manual transfer switch

A manual transfer switch is a changeover switch operated by hand, usually with three positions: source 1, off and source 2. It is common where a portable or small standby generator connects through an inlet, and as a maintenance or bypass switch in larger systems where automatic transfer is not required.

Drawing use

SLD / Schematic

Application

Microgrid systems

Reference family

IEC / IEEE / ANSI

A distinction that matters

A manual transfer switch relies on an operator; an automatic transfer switch senses source failure and acts on its own.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.