6. Operation and maintenance of electric actuators
The actuator needs to lubricate the gears, shaft joints, oil seals and other places during use. For valves that do not move for a long time, they must perform slow step-by-step opening and closing operations, which not only avoids the blocking of the motor, but also It protects the valve body from wear and tear due to excessive force.
Seven, the safe operation of electric actuators
According to national standards, AC motor overload protection should meet the following requirements: short-time or intermittently working motors may not be equipped with overload protection, but when the motor may be blocked during operation, it should be installed to protect the motor from blocking. . In the total pollution source control system, due to the ordinary changes in sewage water quality and the high probability of motor rotor blocking, it is necessary to install a protector. Select the type of protector to skip the starting current, which is less than the locked-rotor current.
The following selection recommendations for single-phase and three-phase asynchronous motors are as follows:
1) Selection of related protectors for single-phase asynchronous motors. In the total pollution source control system project, the electric actuator Zui used is mostly a single-phase asynchronous motor, and the protector can be connected to the live phase of the installed air switch by using a ceramic fuse. Ceramic fuse has no arc and other safety measures.
2) Selection of related protectors for three-phase asynchronous motors. In the total pollution source control system project, there are a small number of three-phase electric actuators, and the lower protector of the air switch can be selected: the integration of the air switch and the AC motor starter. It is also possible to use the integrated circuit breaker, AC contactor, and external heating relay. It is recommended to use the power type of the air switch.
Electric actuators pay attention to safety, and specially introduce two products with different safety specifications for us to choose:
1) Explosion-proof and waterproof type. Working in places with particularly harsh environments such as petroleum and coal mines, it has explosion-proof and waterproof effects. The waterproof Zui high-level can be used for long-term underwater operations.
2) Common type. General chemical and other manufacturing enterprises are suitable for general use.
Eight, the advantages of electric actuators
Corresponding to the manual valve execution method, the electric actuator closing valve has the following advantages:
1) Efficient execution and precise angle control. People can go to the scene and transfer the control signal of the upper computer to the lower computer through the network, and then control the valve to close the valve through the lower computer. The electric actuator can perform the Jing-angle closing valve (regulating type) or directly switch There are two ways to close the valve (switch type). The transmission of control signals through the Internet of Things has become a mainstream method in today's automation and networked fields. The signal is transmitted to the scene through the underlying transmission path of the network, and the effect of real-time and accuracy can be fully achieved.
2) The torque is executed safely, and the switch is convenient and quick. According to the size of the valve, the speed can be adjusted by gearboxes of different specifications, and the larger valve spool can be pushed with a small force. The electronic limit switch is set as the electronic limit, and the mechanical limit is set at the same time. The occurrence of safety protection over-travel phenomenon.
3) Safe electrical protection. The temperature-sensing probe is embedded in the internal mechanism of the actuator as an overheating protection for measuring the locked-rotor of the actuator; the overload alarm is turned on and off, and the internal mechanical structure switch with a certain torque is transmitted to the electric control board through an electric signal to turn it on. Overload and off overload are used as limit protection functions.
to sum up
As an execution terminal, there may be a lot of failure rates, but because of the proper operation and maintenance and reasonable specifications of the installation environment, the stability of this electronic control product can still be guaranteed, and it can become an environmentally friendly, intelligent, and most automated i The most important part of the foundation.
