This standard describes power-actuating devices for valves 3 in. (75 mm) in diameter and larger and slide gates in ordinary water service. Actuators described in this standard are divided into the following types: electric-motor type producing a multiturn rotary motion or used to drive a gearhead drive for a quarter-turn application or electric-motor type with integral drive for quarter-turn applications; cylinder type producing a linear motion; quarter-turn cylinder type producing a rotary motion; and, quarter-turn vane-type actuator producing a rotary motion. Actuators produce a rotary or linear motion to activate a valve or slide gate in open-close, throttling, or modulating service. The following types of actuators are not included in this standard: motor actuators using water, oil, or gas as the driver medium. This standard does not include the following: electric or electronic controls for electric-motor actuators contained within separate enclosures at a location remote from the actuator or actuator floorstand; piping, controls, and positioners for cylinder actuators; intermediate gearhead or mechanism (nonintegral to actuator) between electric power-actuator output and valve/gate stem or shaft; and, the mechanism connecting a cylinder actuator to a valve or slide gate.xi The major revisions to the standard in this edition include the following: a general provision for quarter-turn vane-type actuators is now included; the duty cycle of an actuator is more completely described; digital control interface has been added; torque switch modifications have been added; and, the title has been changed to reflect the AWWA nomenclature changing sluice gate to slide gate.
