1、Torque overload protection Valve electric device is used to operate the valve and was one of the valves connected to the device. The device is driven by electricity, their motion process can be stroke, torque, or to control the size of the axial thrust. As the valve should be the work of electrical
2、device characteristics and utilization depend on the type of valves, fittings and valves regulate the work of the pipeline or equipment location. Therefore, control valve electric device the right choice； consider the prevention of overload (working torque higher than the control torque) has become
3、essential to the occurrence of a ring. Valve electric device right choice should be based on: 1. Operation torque: Operation torque is to select the main valve electrical device parameters. The output torque electric actuator valve operation should be the greatest moment of 1.2 1.5 times. 2. Operati
4、on Thrust: the host structure ofMOTORIZED VALVE ACTUATOR the valve electric device, there are two, one is not configured thrust plate, this time directly to the output torque； the other is equipped with thrust plate, and this time the output torque of the valve stem through the thrust disk nut is co
5、nverted to the output thrust. 3. Number of output shaft rotation circle: valve electric actuator output shaft rotation the number of laps and the valve nominal diameter, stem pitch, thread the first few related, according to M = H / ZS computing (where: M for the electrical installations should be t
6、o meet the total number of rotating ring； H of the valve opening height, mm； S to stem transmission thread pitch, mm； Z to stem the number of screw heads.) 4. Stem Diameter: For multi-turn type valves for the next shot, if the electric actuator allows the maximum stem diameter of the valve stem can
7、not be dispensed, it can not be assembled into electric valve. Therefore, the electrical device hollow output shaft diameter must be greater than specified under the valve stem diameter. For some rotary valves, as well as multi-turn valves in the dark bar valve, although without considering the adop
8、tion of stem diameter, but should also take full account of the matching stem diameter and keyway size, so that work can be assembled . 5. Output Speed: valve Kai, closed fast, easy to produce water hammer phenomenon. Should therefore be under different conditions of use, choose the appropriate Kai
9、and closing speed. 6. The installation, connection method: electric equipment installation for vertical installation, the level of the installation, floor installation； connections as follows: Are thrust plate； stem through (Ming pole multi-turn valves)； dark bar multi-turn； without thrust disk； ste
10、m is not passed； part of the rotation Electric device is widely used, is to achieveproduction program-controlled valves, automatic control and remote control can not be a lack of equipment, its main use in the closed valve. But we can not ignore the special requirements of valve electric device - mu
11、st be able to limit the torque or axial force. Valve Electric installations are usually limited torque Couplings. When the electrical device specification is determined, the control torque is also determined. While in a pre-determined period of time to run when the motor normally does not overload.
12、However, if the following conditions so that it can be overloaded: 1. Power supply voltage is low, are not required torque, the motor stops rotating. 2. Mistakenly set the torque limit adjustment agencies, so that it is greater than stop torque, generated too large a result of continuous torque, the
13、 motor stops rotating. 3. Such as the point of action as intermittent use of heat generated savings of up, more than the allowable temperature rise of the motor. 4. Torque limit for some reason, institutional circuit failure, so that torque is too large. 5. Use of environmental temperature is too hi
14、gh, relative to the heat capacity of the motor down. The above is the excessive number of reasons, for these reasons should be generated by motor overheating in advance, taking into account, and to take measures to prevent overheating. In the past to protect the motor way is to use fuses, overcurren
15、t relays, thermal relays, thermostats, etc., but these approaches also have their pros and cons of this change for the electrical device load devices, is absolutely reliable protection method is not. Must therefore take all methods combined approach. However, as the load on each electrical device is
16、 different, it is difficult to propose a unified approach. In most cases, but generally, you can also find common ground. Overload protection taken by the way, be grouped into two types: 1. Changes in input current to the motor to judge； 2. To judge the heat of the motor itself. These two methods, r
17、egardless of the kind production Summarize of motor thermal capacity must take into account the given time margin. If a single way that will make the heat capacity characteristics of the motor line is difficult. Therefore, over-load should be selected according to the reasons for the action can be a
18、 reliable method - combination of complex ways in order to achieve a comprehensive over-load protection. Rotork electric actuator motor, its embedded in the windings in the motor insulation level consistent with the thermostat, when the reach the rated temperature, motor control loop will be cut off
19、. Thermostat heat capacity is small in itself, and its time-limited features is the motor heat capacity characteristics of the decision, so this is a reliable method. The basic method of overload protection are: 1. Continuous operation of motor jog operation, or overload protection with a thermostat
20、； 2. Locked-rotor protection of motor thermal relay 3. Pairs of short circuit faults using fuse or overcurrent relays. Valve electric device to prevent overload of the right choice and is very much related and should pay attention to. In consideration of economic aspects limiting torques is a contin
21、uous challenge when developing Torque Limiters as an overload protection. The new generation of the backlash-free Torque Limiters. The new generation of the backlash-free Torque Limiters has been designed for being used in power-transmission and servo applications. Important requirements such as bei
22、ng backlash-free, short reaction times and long service life have been further optimized. The constructive benefit is ensured through fast availability of applications after a crash. For limited installations The further development and optimization of the already well established backlash-free Torq
23、ue Limiter series SK has brought about an appropriate design for each application. The transmittable torques can be accurate defined and set. Even in regard to restricted installation space now, the couplings represent the latest state-of-the-art. Areas of applications of the Torque Limiters ranging
24、 from 0.1 to 2,800 Nm can be found in any type of mechanical engineering.Highly dynamic drives are being continously improved by the use of preset Torque Limiters. When the overload occurs the Torque Limiters disengage in milli seconds. The movement of the Actuation ring can be sensed, and used to c
25、ontrol and shut down the machine. Immediate availabillity of the machine after re-engagement of the Torque Limiter can be assured. Increased economic efficiency Optimized disc springs and materials adapted to the use of the coupling allow for the compact and reliable design, better performance and w
26、er mass. Also a long service life and maintenance free operation are importtant consierations when selecting couplings. Smaller couplings combined with a higher torque density additionally result in a cost advantage due to smaller dimensioning. On average the size of the Torque Limiter has been redu
27、ced by approx. 1/3 compared to other available products. This results in a reduced separation of masses in case of a crash due to the reduced weight and a smaller technical diameter. When comparing the facts, it is clear that R + W develops and delivers the most compact Torque Limiters available per
28、iod. A great variety The advantage of ball detent design Torque Limiters is the separation of the drive and the driven elements in milliseconds in case of an overload. Easy handling reliability are further advantages. Machine designs with little installation space or difficult to access areas do however
