Electric Actuators

Introduction

An electric actuator is a mechanical device used to convert electricity into kinetic energy in either a single linear or rotary motion. It automates damper or valve in order to increase process efficiency and complexity. Designs for electric actuators are based on the specific tasks they accomplish within the processes for which they’re intended, and they can vary in both dimension and size.

The motor of an electric actuator can operate on any voltage and is used across many different industries. The most common voltages used in single-phase motors are 115 VAC, 24 VAC, 12 VDC, 24 VDC, 208 VAC and 230 VAC. In addition to these options, three-phase motors also use voltages of 230 VAC and 460 VAC.

An actuator’s brake is mounted on top of the motor. It’s responsible for stopping the media from forcing the valve open when it should be closed by locking the motor rotor in position when not in use.

The motor start capacitor is the third main component of an electric actuator with AC motor. It gives the motor enough power to start. Electric actuators with DC motors do not require a capacitor.

The final critical component of an electric actuator is the two single-pole, double-throw (SPDT) end of travel limit switches. One is for the closed position, and the other is for the open position. These switches provide the adequate number of electrical contacts in the immediate, closed, and open positions.

Basically, an electric actuator is one kind of gear motor which can be of various voltages and is the main torque producing component. To stop extreme current draw, electric actuator motors are generally set with a thermal overload sensor fixed in the motor windings. This sensor is energetic in series with the power source and unlocks the circuit should the motor be excited, then locks the circuit when the motor attains a secure operating temperature.

An electric motor consists of an armature, an electrical winding, and a gear train. When power is supplied to the winding, a magnetic field is generated causing the armature to rotate. The armature will turn as long as there is a control to the windings when the power is cut, the motor discontinues. Typical end of travel limit switches, which are essential for an electric actuator, handles this mission.

These actuators rely on a gear train, which is attached straight from the motor to improve the motor torque and say the output speed of the actuator. The single way to alter the o/p speed is to fit a cycle length control module. This module lets an increase in cycle time only. If a reduction in cycle time is necessary, an alternating actuator with the preferred cycle time and correct output torque must be used.

Types of Electric Actuators

Smart Linear Electric Actuator
Rotary Electric Cut Off Actuator
Linear Electric Cut Off Actuator
Rotary Electric Regulating Type Actuator
SMC Electric Actuator

Smart Linear Electric Actuator

Smart linear electric actuator with the dislocation of linear output. The quality of this actuator is high, the precision material and design are stable, durable and safe, the application environment is broad, similar to all types of valve, ball valves like control, butterfly.

Rotary Electric Cut Off Actuator

Rotary electric cut off actuator allows the integrated standard signal and alters the signal into equivalent angular displacement, so as to mechanically control the valve and achieve the automatic modification task. In the automatic change, the physical, mechanical and bi-directional intrusion free controlling of the regulating system can be recognized. It comprises two parts, namely actuator, and servo amplifier. It can be controlled rapidly or physically at a distance.

Linear Electric Cut Off Actuator

Linear electric cut off actuator is available with two sorts of power supply model such as AC single-phase power supply & three-phase AC power supply. The latest electric actuator is established from the regulator control signal to attain a prearranged linear reciprocating motion. This sequence of electric actuators is employed as the regulating valve actuator, almost with the control valve itself needs a range of action change function, and the opening of the electric actuator valve signal function and physical function. Thus, it is extensively used in various industries like power generation, metallurgical, papermaking, petrochemical, environmental protection and light industries.

Rotary Electric Regulating Type Actuator

This type of actuator is a full electronic actuator gets 4mA to 20mA d.c or 1V to 5Vd.c input signals from the PC, operator or regulator to work with 220V AC single phase power supply like the driving power supply, and is offered with a servo system. An extra servo amplifier is not necessary. The input component “controller” accepts the complex mixed integrated circuits, and is hardened by resin pouring & topic to aging behavior, thus being high inconsistency and opposing to vibration and moisture. When the base and crank is accepted for fitting, the location of the crank zero end can be determined randomly within 0-360℃. In addition, the electrical actuator has the overload, temperature, and torque switch safeties, is high in control precision, product high inconsistency and competent of figuring the angular travel electric regulating valve with a variety of angular travel changeable mechanisms.

SMC Electric Actuator

SMC electric actuators give different advantages, speed and acceleration are controlled and also predictable. Several positions are achievable with high accuracy and repeatability. Almost forces can be automatic. With not require for condensed air, fewer energy costs and infrastructure. SMC’s electric actuators are designed with a center on easy arrangement and process. Function parameters come fixed, in addition, an “Easy Mode” setting choice lets you be operational rapidly. The different types of SMC electric actuators include the following.

Sliders
AC Servo Sliders
Rod & Guided Rod
AC Servo Rod
Slide Tables
Rotary
Grippers
Miniature
Controllers & Drivers

Uses

Generation of rotating movements for different applications: production lines, domestic appliances, toys, tools, etc.
Automation of industrial valves.
Widely used in industrial processes.

advantages of electric actuators

Convenient and easy access to energy, fast signal transmission speed, long signal transmission distance, to facilitate centralized operation and control.
The accuracy and sensitivity are relatively high, and it is convenient and easy to operate with other electric adjustment instruments, and the wiring and installation are simple.
The use effect proves that the electric actuator has good anti-deviation ability, and the output torque or thrust is basically constant, which can well overcome the unbalanced force of the medium and ensure accurate control of the relevant process parameters. Therefore, this product The control accuracy is slightly higher than that of pneumatic actuators.
If equipped with a servo amplifier, the positive and negative effects can be exchanged easily, and the signal valve position status can be easily set. If there is a failure, it must stay in the original position. This ability is the result of pneumatic actuator products. It cannot be achieved because the pneumatic actuator must be equipped with a combined protection system to achieve the function of retaining position.

Disadvantages of electric actuators

Only suitable for places with low explosion-proof requirements and lack of air source. The structure is relatively complex, the thrust is small, and the average failure rate is higher than that of the pneumatic actuator. Due to the complexity of the structure, the technical requirements for on-site maintenance personnel are relatively high.
The operation of the motor will generate heat. If the adjustment frequency is high, it will easily cause the motor to overheat and increase the wear of the reduction gear.
There is also a slower operation. It often takes more time from the output signal of the regulator to the movement of the regulating valve to the specified position in response. The above is the place where the performance is insufficient compared with the pneumatic or hydraulic actuator.