Abnormal Issues in Electric Butterfly Valve Control Circuits

In the field of industrial automation, electric butterfly valves, as a key control device, are widely used in various fluid control scenarios. However, once the control circuit of an electric butterfly valve malfunctions, it can not only affect production efficiency but also pose safety risks. This article will provide a detailed explanation of how to handle abnormal issues in electric butterfly valve control circuits, helping you quickly locate and solve faults to ensure stable operation of the equipment.

When dealing with abnormal issues in the electric butterfly valve control circuit, we first need to start with the basics and carry out a comprehensive and detailed preliminary inspection. This stage of inspection helps us quickly locate the general direction of the problem and lays the foundation for subsequent in-depth troubleshooting. Next, let us start with an external inspection and gradually move into testing the basic circuit.

When handling abnormal issues in electric butterfly valve control circuits, the first step is to conduct a visual inspection of the control circuit. Check whether the wiring is neat, and whether there are signs of damage, breakage, or burning. These obvious damages may be the direct cause of circuit abnormalities. At the same time, check whether the terminals are loose or oxidized, and whether components on the circuit board show deformation, discoloration, or leakage. These minor issues may cause poor contact in the circuit or component failure.

Use a multimeter to measure the power supply voltage of the control circuit, ensuring that it is within the working voltage range specified for the electric butterfly valve. If the voltage is abnormal, the problem may lie in the power lines, transformer, or fuse. Check for open circuits, short circuits, or poor contact. The stability of the power supply voltage is crucial for the normal operation of the electric butterfly valve.

The normality of control signals directly affects the operation of the electric butterfly valve. At the input end of the control circuit, use an oscilloscope or signal generator to measure parameters such as amplitude, frequency, and waveform of the signal, and compare them with signals during normal operation. If the signal is abnormal, trace it back to the control system and check whether the related controllers and sensors are functioning properly.

After completing the preliminary visual and basic circuit inspection, the next step is to go deeper into the component level and check key components one by one. This step is crucial because many abnormalities in control circuits are often caused by faults in certain key components. By using professional testing tools, we can accurately determine whether a component is damaged and take timely repair or replacement measures.

Key components in the control circuit, such as relays, contactors, solenoid valves, capacitors, resistors, and chips, need to be tested using corresponding tools. For example, use a multimeter to measure whether the resistance value matches the nominal value, check whether capacitors leak or short-circuit, and verify whether the contacts of relays and contactors can normally engage and disengage. Damage to these components may lead to circuit malfunction.

Use a continuity tester or the resistance setting on a multimeter to check whether the circuit lines are conductive. Focus on long connecting wires, conduit wiring, and areas prone to mechanical damage, to see if there are internal breaks that are not visually apparent. For damaged or broken wires, cut off the affected part, reconnect it, and properly insulate it. If the wires are aged or internally shorted, it is recommended to replace them with new ones.

For loose terminals, retighten them; for oxidized terminals, clean them with sandpaper to ensure good contact. Good contact is the foundation for normal circuit operation.

Replace Damaged Components: For components confirmed as damaged through testing, such as relays, capacitors, and chips, replace them promptly with new components of the same model and specifications. During replacement, pay attention to soldering quality to avoid cold solder joints or short circuits. For plug-in components, ensure they are firmly installed.

Handle Power Supply Voltage Abnormalities: If abnormal voltage is caused by transformer failure, repair or replace the transformer; if a fuse is blown, determine the cause of the fuse and replace it with a fuse of the same specification after resolving the issue.

Adjust Control Signals: If abnormal control signals are due to incorrect parameter settings in the control system, readjust the parameters; if caused by sensor faults leading to inaccurate signals, repair or replace the sensor. If there is interference in signal transmission lines, take shielding measures, such as using shielded cables or adding filters.

After the previous component testing and repair, the next critical step is to perform a comprehensive inspection and testing of the repaired equipment. This step is the last line of defense to ensure long-term stable operation of the equipment. Only through rigorous inspection and testing can we confirm that all faults have been thoroughly resolved and the equipment can be safely put into use.

After repair, check again without power whether the control circuit connections are correct, components are firmly installed, and lines are conductive. Use a multimeter to measure resistance values in various parts to ensure they are within normal range, preventing short circuits or open circuits.

Turn on the power and observe the operation of the control circuit. Check whether the power indicator light is functioning normally, and measure whether voltages at key nodes meet design requirements. Test again whether the input and output of control signals are normal, observe whether the electric butterfly valve can accurately open and close according to the control signals, and monitor motor operation for abnormal sounds or vibrations.

Perform actual functional tests of the electric butterfly valve, including full open, full close, and control at different openings. Check the flexibility, accuracy, and stability of its operation. Verify whether the control precision of the electric butterfly valve meets requirements, such as achieving the specified opening within the designated time and maintaining stable openings under different working conditions.

Allow the electric butterfly valve to operate under actual working conditions for a period while continuously monitoring the control circuit’s performance, including voltage and current stability, as well as the valve’s operation. Observe for abnormal heat, odors, or noise to ensure long-term stable operation of both the control circuit and electric butterfly valve.

After completing basic repairs and testing, if the electric butterfly valve control circuit still has issues or more complex situations arise, it is necessary to enter the stage of special issue handling. This section provides detailed solutions for some common yet complex faults, helping you tackle difficult problems.

When DCS control is used for a 4–20 mA DC actuator positioning signal, it is necessary to ensure that the set signal and feedback signal can accurately output an error signal on the circuit board. After amplification, this error signal determines the motor’s forward or reverse rotation and drives the corresponding solid-state relay. The motor’s rotation direction is adjusted by the output shaft of the reduction gearbox, which drives the lever arm or the valve opening. If signals are abnormal, check the signal processing section of the circuit board to ensure accurate and stable signal transmission.

When the load torque of the electric butterfly valve is too high, the over-torque protection mechanism may be triggered. At this time, the micro switch transmits an over-torque signal to the circuit board to prevent damage to the drive unit. If the over-torque signal is triggered frequently, check for faults in the mechanical transmission, such as loose connecting parts or damaged micro switches. Adjust the over-torque setpoint if necessary to ensure stable operation under normal load.

Motor overheating is a common issue for electric butterfly valves. When the motor temperature is too high, the thermal switch cuts off the power to protect the motor. If the motor overheats, first check the motor’s heat dissipation and ensure proper ventilation. If the motor temperature is normal but the thermal controller on the circuit board is damaged, replace the controller. Also, check whether the motor supply voltage is normal to avoid overheating caused by overvoltage.

Mechanical component faults may also cause abnormal control circuits in electric butterfly valves. For example, the output shaft of the gearbox may be damaged due to excessive load, preventing normal motor drive. In such cases, disassemble, clean, and relubricate the gearbox. Also, inspect mechanical transmission parts for wear or damage, and replace if necessary.

Vibration is a common problem during electric butterfly valve operation, usually caused by other large equipment or design and construction defects. Vibration may loosen mechanical parts or even damage the circuit board. To resolve vibration issues, properly secure the actuator and avoid exposure to vibration sources. If vibration problems persist, consider replacing the actuator or modifying the structure.

Damage to solid-state relays may cause circuit shorts and affect normal operation. If a solid-state relay is damaged, replace it immediately. Ensure the relay’s model and specifications match the original equipment to avoid new issues.

Motor commutation capacitor faults are easy to identify. If the electric butterfly valve works normally in manual mode but cannot operate in automatic mode, the commutation capacitor may be damaged. Check and replace the capacitor as needed, and ensure the motor supply voltage is normal for proper operation.

Circuit board faults are one of the common causes of abnormal control circuits in electric butterfly valves. If the circuit board completely loses power, it may be damaged. In such cases, replace the board, ensuring the new board matches the model and specifications of the original to prevent new problems.

Handling abnormal issues in electric butterfly valve control circuits requires a systematic approach and meticulous inspection. By progressing from visual inspection to component testing, followed by post-repair testing and long-term monitoring, abnormal circuit problems can be fully resolved. Additionally, addressing special issues with corresponding solutions and preventive measures effectively prevents recurrence. This article aims to help you better manage abnormal issues in electric butterfly valve control circuits and ensure stable operation of the equipment.