1. The valve position of the electric actuator is lost:
1) Battery power is lost
When the incremental encoder is selected to measure the stroke, it is necessary for the fulfillment mechanism to have a battery as an auxiliary power supply, the AC power supply disappears, the change of the valve position of the electric actuator can still be detected by the incremental encoder, the full open position and the full close position of the electric actuator will not change, if the AC power supply disappears, the battery power supply is exhausted, when the actual valve position of the electric actuator changes, the incremental encoder cannot detect the change of the valve position, resulting in the loss of the valve position, and when the AC power supply is restored again, the products of some manufacturers acquiesce to the valve position at 50%; Now some manufacturers who use incremental encoders have made improvements in hardware, adding capacitor loops, and when the AC power disappears, the capacitors are used to store electrical energy to save the valve position, but the electric actuator cannot be operated manually when there is no battery power supply, otherwise the valve position will still be lost. Therefore, when the battery is low, replace the battery in time.
2) Hardware damage
The encoder of the electric actuator is broken, the input voltage of the encoder is too low, the gear of the stroke transmission equipment is damaged, the encoder circuit board is corroded, and the motherboard travel detection and storage components are damaged, which can lead to abnormal changes or discarding of the valve position.
2. Torque problem of electric actuation mechanism:
1) Torque maintenance rejection
Measuring the output torque of the electric actuation mechanism, there are mainly mechanical maintenance switches, motor current and voltage power measurement and calculation torque, and sensor-type maintenance equipment: mechanical torque maintenance switches are used more before 2000, which belongs to a transitional product, and now some low-end electric fulfillment mechanisms are still used, and this kind of torque maintenance switch can only supply the switching quantity, which is used for torque maintenance, and can not supply real-time data of process torque, and the measurement error is large; The torque is calculated by using the motor current voltage and the phase angle between the current and voltage, which is completed by a software program; The sensor-type torque maintenance equipment combines the axial deformation of the first-stage worm of the electric actuator with the pressure sensor, expands the voltage output by the pressure sensor through the circuit board, and then inputs the signal to the control motherboard to obtain the real-time torque value of the electric actuator.
The torque maintenance refusal is mainly manifested in the tripping of the AC power supply of the accomplishment mechanism, the serious wear of the worm gear and worm of the electric actuation mechanism, the tortuous deformation of the door rod, and even the twisting of the connecting screw between the electric actuator and the valve. When the valve torque is selected, it is necessary to ensure that the fulfillment mechanism firmly opens and closes the valve, and the torque of the electric actuator is required not to exceed the maximum torque that the valve door lever can accept, there is a certain difficulty in parameter setting, because the maximum torque that each valve door lever can accept, it is often not easy to obtain, the electric actuator uses the manufacturer to set the torque parameters according to experience, first set the small torque maintenance value, if the torque maintenance action, and then the torque maintenance parameter is set appropriately, Until the valve can be opened and closed normally in the cold state, if the torque maintenance action is in the hot state, continue to increase the torque maintenance value appropriately to ensure that the valve can be opened and closed normally in the hot state.
2) Torque maintenance malfunction
In the case of light manual operation of the electric fulfillment mechanism, the over-torque maintenance action is presented, and the torque maintenance value is set too small, for the intelligent electric accomplishment mechanism, observe the torque value prompt on the LCD screen or the indicator light shows the over-torque information, and after rolling in the opposite direction, the over-torque signal in the original direction should disappear. Otherwise, the motherboard or torque detection equipment should be replaced, and eliminated one by one.
Regarding the mechanical torque detection equipment, roll the motor fulfillment mechanism in the opposite direction, and check that the torque switch should be disconnected, otherwise, the torque maintenance switch should be replaced; If the moment policyholder has been set to the maximum and still shows excessive torque, it should be considered whether the torque selection of the electric actuator is too small.
3. The motor of the electric fulfillment mechanism rolls, and the output shaft of the fulfillment mechanism does not roll, and the specific reasons may be:
1) The electric accomplishment mechanism engages on the manual side, and after the motor of the electric actuation mechanism rolls, the switching device fails to mesh to the motor side, resulting in the motor idling.
2) The worm gear driven by the electric accomplishment mechanism is worn and slipped, resulting in the motor idling and the output spindle of the fulfillment mechanism not rolling.
3) The three-phase power line of the motor has a one-phase touch that is not reliable, resulting in the motor not rotating from time to time.
Regarding the idling of the motor of the electric actuation mechanism, after judging that there is no problem with the power supply, it is necessary to open the first-level worm gear and worm box of the electric actuation mechanism to check the wear and tear of the worm gear and worm, if the wear is serious, it can only be returned to the factory for repair, or replace the new electric actuation mechanism; The problem of switching equipment can generally be repaired on site according to the working principle of switching equipment of different electric fulfillment mechanisms.
4. The motor of the electric fulfillment mechanism may be overheated due to the following reasons:
1) The frequent operation of the electric fulfillment mechanism leads to the real overheating of the motor and triggers maintenance actions.
2) The thermal resistance type temperature measuring element is disconnected or the terminal is not touched, and the generator overheating signal is mistaken.
3) The rotor bearing of the motor is damaged and cannot be rolled, and the motor is overheated due to the motor stalling.
Regarding the damage of the motor bearing, the bearing should be replaced; When the temperature measuring element is damaged, the motor should be replaced, because the stator coil needs to be disassembled to replace the temperature measuring element alone, the cost is too large, and the cost is to meet the purchase of a new motor with a power of several hundred watts.
5. The electric fulfillment mechanism cannot be operated locally or remotely, and the reasons may be:
1) Power board problem, the power board supplies control power to the motherboard, if the power board is faulty, it may cause the remote place to be unable to operate.
2) Motherboard problems, which may lead to the inability to perform control instructions.
3) Power supply problem, the electric equipment detects that the power supply is out of phase or there is no power supply, and the electric fulfillment mechanism cannot operate.
Such problems can only be eliminated one by one with replacement motherboards and power boards, and due to the place of application, the conditions for testing circuit boards are generally not available.
6. There is no feedback from the electric fulfillment mechanism that is fully open and closed, and the reasons may be:
1) The terminal azimuth relay cannot be firmly closed or opened.
2) The relay is not set correctly.
3) Motherboard issues.
When processing, check the terminal orientation setting first to ensure that the settings are correct; Regarding the relay problem, if the azimuth relay is installed independently, the azimuth relay is replaced; If the azimuth relay is soldered to the motherboard, replace the motherboard.
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