How To Troubleshoot An Open Circuit Fault Within A Control Circuit

Electrical issues can occur in different forms. In case you power on a machine but it does on start, there is a high possibility that the problem has something to do with an electrical fault. This could be a mechanical problem. This article is aiming to address some of the common problems in electrical circuits. An electrical circuit fault might be within the power circuit or the control circuit. Besides, it can take different forms such as being an open fault or a short circuit. Below are some of the most common faults that face electrical systems.

If you have any kind of experience in handling electrical tasks, troubleshooting an open circuit fault within a control circuit might seem so complicated. But that is not true, provided you have proper guidelines and you make sure that you follow all the given steps. Here are is a general procedure which will guide you to begin from the center of the problem and by doing so, you will be able to know which direction to take. It is always great to start from the control transformer as it is found at the center of the circuit. Besides, it is connected to both power and control circuits.

Steps for troubleshooting

Normally an open circuit fault refers to any kind of fault that halts the machine operation due to an open wire or component. Troubleshooting an open circuit within the control unit consists of the following:

  1. Having the general information about the circuit

First, you have to begin by analyzing the schematic diagram of the circuit so as to have a collective view.

  • Carefully open the control panel

You must have a voltmeter that you will use to check voltage. Verify if the voltmeter is properly functioning

  • Check the voltage

You have to check the voltages along with both two terminals upon the secondary of the control transformer. In case the voltage reading is different from what they should be, that means that there a fault in the power circuit. But if the voltage readings are correct, the OL is still on its ON position while the contactor is not energized, then the fault lies within the control circuit. It is also possible that the fault might also be within the power circuit.

When the voltage reading is correct along terminal 1 and 2,  the OL is still maintaining the ON position while the contractor is still energized, this means that the fault lies within the control panel. This is an open circuit fault in the panel. Now you will have to troubleshoot the system in a logical manner until when the correct voltage becomes absent.

  • Inspect the voltage along with terminal 1 above the fuse of the control circuit as well as terminal 2 over the secondary of the control transformer. In case the voltage readings are still correct, then you will have to jump to step 5. But if the voltage readings are incorrect, then you can conclude that the fault is at terminal 1 as the wire will be open above the fuse to the terminal 2 upon the secondary of the transformer.
  • Inspect the voltage along with terminal 1 above the control circuit’s fuse as well as terminal above the neutral link. In case the voltage readings are correct, then jump to step 6. However, if the voltage readings are incorrect, it means that terminal 2 is open from above the neutral link along with the terminal upon the secondary of the transformer.
  • Inspect the voltage upon wire 1 below the control fuse as well as terminal 2 voltage above the neutral link. In case the voltage readings are correct, just move on to step 7. However, if the voltage readings are incorrect, that means the control fuse is open. If this is the issue, that means there is a short circuit or a ground fault. If the fuse is not open, then there must be an open circuit fault. This is the initial sign that the issue lies in an open circuit fault.
  • Inspect the voltage upon wire 1 below the control fuse as well as wire 2 below the neutral link. Move on to step 8 in case the voltage reading is correct, as it means that the neutral link is open.
  • By using wire 2 as a reference due to the fact that the voltage below the fuse reads correctly. Do your measurements starting from the left moving all the way to the right and back to the top and then to the bottom again until you identify where there is no voltage. In case there is still no correct voltage, then move on to step 9.
  • Inspect the voltage along the point situate to the left side of 1OL by using wire 2 as your reference. Move on to step 10 in case the voltage readings are correct. In case the voltage readings are incorrect, then that means wire 1 is open from below the fuse to the left of the closed contacts for 1OL.
  • Move on to inspect the voltage along with the next point that is situated on the right side of 1OL using wire 2 as your reference. In case the voltage reading is correct then move on to step 11. In case the voltage readings are incorrect then the normally closed contact for 1OL must be the ones which are open.
  • Inspect the voltage upon D which is above terminal 3 while still using wire 2 as your reference. In case the voltage readings are correct then move on to step 12. In case the voltage readings are incorrect that means wire 3 is open within the upper terminal 3 and 1OL right-side terminal.

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