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Electric valve actuators control the opening and closing of valves. With a motor drive that provides torque to operate the valve, these actuators are frequently used on multi-turn valves such as gate or globe and also on ball, plug and other quarter-turn valves. Electric valve actuators are ubiquitous in today’s industrial space. They can be found in various industries and applications, including water treatment and wastewater plants, hydroelectric power generation, oil refineries, shipbuilding and numerous processing industries such as chemicals, food and beverage, pulp and paper, and pharmaceuticals.

Choosing Right Power Source

If a plant chooses to use electric actuator, it must have a power source available. So, it is vital to decide the categories electricity that is available now.

It mainly can divide into three types, including Single-phase AC power, There-phase AC power, DC power. The power source will be used to operate the motor through a set of reversing cont-actors, either located within the actuator, or in some cases located in a remote cabinet. Why it is important to make sure the actuator is manufactured and supplied, the power source must be ability of supplying the proper voltage and current required by electric actuator to run the valve. It may be required to operate the valve as an open and close or modulating actuator.

The mode of controls

when we determine the type of power source. Next is what operate the electric actuator, in another words, how the actuator will be controlled.

The main types of controls can easily list two, Local Controls and Remote Controls. Local controls are easily to understand, they are mounted directly to the actuator.

In the realm of remote-control mechanisms, discreet signals for opening and closing are commonly utilized with valves for both open/close functions and modulating services. These signals are transmitted via pushbuttons or switches (known as pilot devices) from either a PLC or a remote-control station to the actuator. Typically, control power is supplied as either a 24VDC or 110VAC signal. The power for remote control can either be sourced on-site or provided through actuators that are equipped with a control power transformer (CPT), ensuring the necessary voltage for the customer’s control system.

It is commonly that using Analog signals modulate valves, analog signals denote continuous electrical signals representing the measured quantity. These analog signals can hinge on either voltage or current. The signal’s scale adjusts according to the range of the measured variable. Secondly, it is digital bus communication, For both open/close valves and modulating valves, the option of digital bus communication is available. This method, also known as fieldbus or two-wire control, facilitates the transmission of control signals along wires linking a set of actuators with a digital bus controller. Before implementing fieldbus communication, it’s crucial to identify the protocol to be utilized. Among the protocols available are: 1. Foundation Fieldbus 2. Profibus 3. Modbus RTU (Remote Terminal Unit) 4. Modbus TCP/IP (Transmission Control Protocol/Internet Protocol) 5. Hart 6. Ethernet IP (Internet Protocol) 7. Device Net 8. Back Net.

If the site is communicating via fieldbus, make sure the actuator can use the same protocol. Some actuators can provide the option to operate with discreet inputs and fieldbus communication.

Other Things Need Pay Attention to 

1. Feedback: Feedback are the signals coming from the actuator to the control system, also referred to as output signals. (Types: feedback, discreet feedback signals, bus communication feedback, Limit/torque switches, Visual position feedback.)
2.Commissioning: Commissioning of an actuator is required to ensure proper operation of the valve and integration to the control system. Commissioning requirements may include verification or setting of end positions, setting of torque and the feedback signals. (types: Intrusive actuator, non-intrusive actuators)
3.Security: According to the level of security, it can be divided into physical security and system security (Bluetooth, permissive signal, interlock signal.)
4.Backup power.
5.Fail safe.

Conclusion:

In the field of industrial automation, electric actuators emerge as a standout choice celebrated for their exceptional precision, versatility, and energy efficiency. With the ability to precisely regulate speed, position, and force, they thrive in dynamic operational environments, catering perfectly to applications requiring precise control. Their increasing popularity stems from their ability to consume energy on demand and their environmentally conscious design, aligning with evolving global mandates for sustainability, particularly within the industrial sector. Additionally, the utilization of electricity enables the integration of renewable energy sources such as solar and wind power. Moreover, their streamlined design and reduced maintenance needs further enhance their appeal.