You should check the voltage on X1 at the top of the control circuit fuse and X2 at the top of the neutral link.
If the correct voltage is not present, then X1 wire is open from the top of the fuse to the terminal on the secondary of the transformer.
If the correct voltage is present, continue to Step 5.Step 4. You should check the voltage on X1 at the top of the control circuit fuse and X2 terminal at the secondary of the control transformer. If the voltage changes from a good reading on one device to a different reading on the next device in logical order, then the device or wire in between those readings is open. Since the correct voltage is present, we must troubleshoot the system in a logical order until we lose the correct voltage. From the schematic in figure 1, you should have read 120 volts at terminals X1 and X2. For this scenario, the fault is an open-circuit fault and inside the panel. The correct voltage is present at X1 and X2, the contactor is not energized and the OL is not tripped, then the problem is in the control circuit. Scenario is the motor does not start when the start button is pressed. If correct voltage is present, the contactor is not energized and the OL is not tripped, then the problem is in the control circuit. If correct voltage is present and the contactor is energized, then the problem is in the power circuit. If correct voltage is not present, then the problem is in the power circuit. You should check the voltage at the X1 and X2 terminals at the secondary of the control transformer. You must carefully open the control panel with power energized since voltage checks will need to be made. Step 1.You must analyze the schematic diagram for a general circuit overview. Remember that the first three steps will be the same for all faults. Let’s develop our procedure for troubleshooting an open circuit in the control circuit. Open-circuit faults – An open circuit fault is any fault that stops the operation of a machine due to an open wire or component. Open-Circuit Faults in the Control Circuit
We will now investigate open circuit faults in the control circuit. The first fault we will investigate is the open-circuit fault. For simplicity’s sake, we will now take one area and one type of fault at a time. There is no one procedure that can guide you through any given problem. The first three steps of this procedure will be the same for all faults and the rest will be completed throughout this chapter in more than one procedure. The control transformer is a good place to start since it is in the middle of the circuit and is part of the power and control circuits. This general troubleshooting procedure is designed to start in the middle of the problem area and give us the best idea of which direction to go. The fault could also be many different types, such as, open-circuit fault, short-circuit fault or a ground fault. This fault could be located in either the power circuit or the control circuit. We will focus on just the electrical circuit faults for now. The machine does not start when the start button is pressed.Īt this point, the problem could be mechanical or electrical.