This standard covers power-actuating devices for valves 3 in. (75 mm) in diameter and larger and sluice gates in ordinary water service. This standard covers actuators purchased by parties defined as the purchaser in Sec. 1.3. 1.1.1 Actuator types. Actuators covered by this standard are divided into the following types: 1.1.1.1 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, as defined in Sec. 3.1.2; 1.1.2 Cylinder type producing a linear motion; 1.1.1.3 Quarter-turn cylinder type producing a rotary motion; 1.1.2 Actuator function. Actuators shall produce a rotary or linear motion to activate a valve or sluice gate in open-close, throttling, or modulating service. 1.2.1 Excluded actuators. The following types of actuators are not included in this standard: Motor actuators using water, oil, or gas as the driver medium; and Electric-motor actuators with direct-current (DC) motors and multispeed motors. 1.2.2 Other exclusions. This standard does not include the following: Electric/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 sluice gate. The major revisions in this edition of AWWA C540 include the following: A general provision for quarter-turn cylinder and electric actuators is now included; Section 3.15 on stop limiting devices has been added for quarter-turn actuators; A proof-of-design test for quarter-turn cylinder actuators is included (Sec. 6.2.4); and The definitions for purchaser, supplier, and corrosion-resistant metals have either been modified or added.