Electric Actuators

FAQs about electric actuators

• What is an electric actuator?

  In this context, we are referring to quarter-turn electric actuators that generate rotational force through a 90-degree movement. While other types, such as multi-turn and linear actuators exist, quarter-turn models are most commonly used for ball, butterfly, globe and plug valves. An electric actuator combines a motor and gearbox in one enclosed assembly to open or close a valve. Features can include manual override, position indicator and internal microswitches that provide feedback to PLCs or other control systems. Modulating actuators allow intermediate positioning for proportional control rather than simple open or close operation. Standard voltages include 12v DC, 24v AC/DC, 110v AC, 230v AC and 415v AC, with single and three phase motors available. Electrical protection ratings are typically IP67, with IECEx Exd options available for hazardous environments.

• How does an electric actuator work?

  Quarter-turn electric actuators use an electric motor to drive a gearbox, converting electrical energy into controlled rotational movement. The internal gearing determines output speed. As a general rule, higher torque models rotate more slowly due to gearbox ratios. Internal cams mounted on the output shaft cut power to the motor once the actuator reaches its preset open or closed position. In modulating actuators, a 4–20 mA signal controls the shaft position, allowing the actuator to move to any point within the 90-degree range for proportional flow control.

• How do I size an electric actuator?

  Correct sizing is based on the torque requirement of the valve being automated. Start by identifying the working torque in Nm from the valve data sheet, which reflects the torque required under operating pressure, temperature and media conditions. Add a minimum 30 per cent safety factor to this value. Always check the valve’s breakaway torque, particularly with butterfly valves, where initial unseating torque can exceed running torque. Select an actuator with a rated torque equal to or greater than the calculated requirement. You should also confirm that the actuator mounting pad matches the valve’s ISO 5211 hole pattern. In some cases, stepping up one actuator size may simplify mounting or adaptor selection.

• How long will my electric actuator last?

  Service life depends on environmental conditions, cycle frequency and correct installation. In most cases, actuator longevity is influenced more by environment and ingress protection than by mechanical wear. Always use an IP67-rated gland connection for cable entry. Incorrect or low-rated cable glands are a common cause of water ingress and subsequent failure. When installed correctly, many of our actuators have operated for decades without requiring maintenance. Duty cycle must also be observed. As electric actuators are sealed units, they rely on appropriate rest periods for heat dissipation based on their model rating. If installed correctly we have units that have been working for decades trouble free.

• How do I install an electric actuator?

  Electric actuators can be mounted directly to valves with ISO 5211 mounting pads or via custom adaptors where required. They are suitable for installation in horizontal or vertical orientations, although mounting with the position indicator facing upward is recommended. Avoid mounting upside down, as grease migration within the gearbox can occur. Drive adaptors can be supplied to suit different valve stem configurations. Internal zero-voltage microswitches are supplied as standard to provide open and close feedback signals to control systems. Adjustable striker cams allow precise limit setting, and additional microswitches can be fitted if required. If torque limiting is required, this must be factory fitted and cannot be retrofitted in the field. Electrical installation should be completed by a qualified electrician or instrument technician, particularly for IECEx-rated Exd models.

• What are typical uses of an electric actuator?

  Electric actuators are commonly used to automate ball, butterfly and plug valves in water treatment plants, mining operations, food production facilities and petrochemical environments. Beyond valve automation, they can be used wherever controlled 90-degree rotation is required. IP67-rated models provide protection against harsh weather and temporary immersion. IECEx-certified Exd actuators are suitable for hazardous areas in accordance with applicable standards.

• How long will it take for my product to get to me?

  Delivery time depends on your location and selected freight method. Express freight typically provides next business day delivery to metropolitan areas in Australia for consignments under 5 kg. Free freight is sent via road transport and generally takes between 1 and 10 days, depending on location, with an average of around 3 days.

• What warranty do I get?

  All electric actuators supplied by Process Systems include a 12-month warranty. Every unit is tested and inspected prior to dispatch to ensure quality and performance. When installed and operated correctly, these actuators are designed to deliver long-term reliability in demanding industrial environments.