Problems with DN200 electric control valve
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The DN200 electric control valve is in continuous operation. Now, the signal is given but nothing happens; however, when the valve is disconnected, everything works normally and the pressure difference is not high. I don’t know why, please help.
“What does “cut out the valve” mean? The pressure difference isn’t very large either; is that pressure difference really necessary? I’m confused, please explain clearly. Generally, the best way to determine whether a valve is functioning properly is to use a walkie-talkie to coordinate actions with the personnel in the control room on-site, and assess the level of synchronization to judge its effectiveness. For reference.
When cut out, it follows a secondary path; the valve does not carry the medium. During normal operation, the differential pressure across the valve is not significant.
This post was last edited by tiger2010 on 2022-2-8 at 18:28. Are there any photos inside the electric motor? How long has it been in use? Has the capacity of the internal start-up/run capacitors decreased? If no signal is given, does it not function only when fully closed, or in all positions?
If it can be cut, try moving it back and forth a few times first. If large movements work fine, then try smaller movements – it’s likely still a problem with the valve
It could also be a problem with the control system wiring; have the technician check it carefully
The torque setting is estimated to be inappropriate. After the valve is cut out, it operates under no-load conditions (without any fluid). In this state, the electric valve requires only a modest amount of torque to be opened or closed. When the medium is introduced, the torque should be increased appropriately.
It’s likely a problem with the motor of the electric actuator; it is recommended to check whether the actual voltage matches the rated voltage. Another possibility is that there might be issues such as missing teeth or excessive tooth spacing in the gear connection between the electric actuator and the valve; it’s necessary to investigate this step by step
If the requirements are not strict, the secondary line can be slightly opened to serve a voltage equalization purpose, while the main line is used for adjustment.
Most likely: a fault in the drive motor of the actuator (severely insufficient driving force), or a mechanical fault with the valve.
Does the electric headband come with a handwheel? Turn the handwheel switch to see if the valve is heavy. It is possible that over time, the bottom valve becomes heavier to operate, resulting in insufficient torque from the electric actuator.