How to Troubleshoot MOV

In this article, you will find how you can troubleshoot MOV with each problem and its solutions.

Introduction

Welcome guys. Today we will see the maintenance jobs on MOV. MOVs are used in large pipelines. The MOVs are usually large and also require a large amount of torque.

So, let us start with this article for troubleshooting problems in the MOV.

Problem> MOV not operating as per command in remote mode

Solutions:

1. Check whether the MOV is in power ON condition or not. If it is in power-off condition, then ask an electrical engineer to check the power supply. If the power supply is ok as per the electric engineer, then check all the cards of the MOV as per vendor instructions (All MOVs have different types of cards. Refer to their specific manuals)
2. Check whether the MOV is in local remote or stop mode. For operation in remote mode, the MOV should be in remote mode. If MOV is in stop mode, then the MOV will not operate. Also, if MOV is in remote mode from the button, then make sure that the display of the MOV also shows remote mode. If the display shows local mode or stop mode, then the button might not be working. Attend to the problem of the button. If still the MOV is not operating, then check the cards.
3. If MOV has a torque trip alarm, then try to operate the MOV through the hand wheel. If the MOV is hard to operate, then rouse it through the hand wheel. If it is smooth in operation, then check the torque value and set it as per the datasheet. The torque value might be less and this will be the reason for the torque trip. If still the MOV is showing torque trip, then check the cards.
4. If the MOV is showing a thermostat alarm, then wait for a few minutes. The thermostat alarm comes when the MOV is operated more times and the motor is heated. If MOV is not operated and the thermostat alarm persists, then check the thermostat.
5. If still MOV is not operating, check all the connections. Some connections might be incorrect.

Problem> MOV not operating as per command in local mode

Solutions:

1. Check whether the MOV is in power ON condition or not. If it is in power-off condition, then ask the electrical engineer to check the power supply. If the power supply is ok as per the electrical engineer, then check all the cards of the MOV as per vendor instructions (All MOVs have different types of cards. Refer to their specific manuals)
2. Check whether the MOV is in local or remote or stop mode. For operation in local mode, the MOV should be in local mode. If MOV is in stop mode, then the MOV will not operate. Also, if MOV is in local mode from the button, then make sure that the display of the MOV also shows local mode. If the display shows remote mode or stop mode, then the button might not be working. Attend to the problem of the button. If still the MOV is not operating, then check the cards.
3. If MOV has a torque trip alarm, then try to operate the MOV through the hand wheel. If the MOV is hard to operate, then rouse it through the hand wheel. If it is smooth in operation, then check the torque value and set it as per the datasheet. The torque value might be less and this will be the reason for the torque trip. If still the MOV is showing torque trip, then check the cards.
4. If the MOV is showing a thermostat alarm, then wait for a few minutes. The thermostat alarm comes when the MOV is operated more times and the motor is heated. If MOV is not operated and the thermostat alarm persists, then check the thermostat.
5. If still MOV is not operating, check all the connections. Some connections might be incorrect.

Problem> MOV has incorrect feedback.

Solutions:

1. Set the feedback of the MOV.
2. The position sensor can be faulty. Check the position sensor’s connection.
3. The open feedback element or close feedback element’s contact selection from the settings might be incorrect. Correct the settings and make proper connections.
4. Also, the open feedback element or closed feedback element can be in a faulty condition. Check the connections. If connections are ok, then replace the open feedback element or close feedback element.

Problem> MOV operating in the reverse direction.

Solutions:

1. Check the setting has the direction of operation. Correct it as per requirement.

Most of the time, the problem will be solved using the above steps. Some typical problems in the MOV can come. Check all the settings again.

If still the MOV is having issues then check the diagnostics and refer to the manual of the MOV for detailed troubleshooting.

EndNote

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