【正文】 on level consistent with the thermostat, when the reach the rated temperature, motor control loop will be cut off. Thermostat heat capacity is small in itself, and its timelimited 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。 stem is not passed。 dark bar multiturn。 connections as follows: Are thrust plate。 S to stem transmission thread pitch, mm。 the other is equipped with thrust plate, and this time the output torque of the valve stem through the thrust disk nut is converted 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 puting (where: M for the electrical installations should be to meet the total number of rotating ring。Torque overload protectionValve 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 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 bee 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 ~ times. 2. Operation 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。 H of the valve opening height, mm。 Z to stem the number of screw heads.) 4. Stem Diameter: For multiturn type valves for the next shot, if the electric actuator allows the maximum stem diameter of the valve stem can 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 multiturn valves in the dark bar valve, although without considering the adoption 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 and closing speed. 6. The installation, connection method: electric equipment installation for vertical installation, the level of the installation, floor installation。 stem through (Ming pole multiturn valves)。 without thrust disk。 part of the rotation Electric device is widely used, is to achieveproduction programcontrolled 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 must 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 predetermined period of time to run when the motor normally does not overload. 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 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 high, relative to the heat capacity of the motor down. The above is the excessive number of reasons, for these reasons should be generated by mot