Electric motor actuator (MOV)

ISA 5.1-2009/2022 (final control element actuators) / PIP PIC001

Drawn as

A valve with a circle containing "M" on top of its stem.

Meaning

Electric motor actuator: large isolation valves, pipeline and firewater valves, and tank valves where air is not available. It fails in place (last position) on power loss.

Variants

Some legends draw a square with M
An integral control unit may be shown as a small box beside the M