Over-current faults in DC centrifugal fans can cause disruptions and potential damage. There are several possible causes for over-current. A short circuit within the motor windings or in the electrical wiring connected to the fan is a common culprit. If the insulation of the wires is damaged or there is a manufacturing defect in the motor, it can lead to a short circuit, causing a sudden increase in current.

Mechanical problems can also lead to over-current. For example, if the fan blades are hitting an obstruction or there is excessive friction in the bearings, the motor will have to work harder, drawing more current. Another factor could be incorrect voltage application. If a voltage higher than the rated voltage is supplied to the fan, the current will increase according to Ohm's law.

To troubleshoot over-current faults, the first step is to check the electrical connections. Inspect the wires for any signs of damage or loose connections. Use a multimeter to test the resistance of the motor windings. If the resistance is significantly lower than the normal value, it indicates a possible short circuit. For mechanical issues, visually inspect the fan blades and bearings. Ensure the fan is rotating freely and there are no obstructions. Adjusting the voltage supply to the correct level and monitoring the current after making any changes can help identify if the problem was related to incorrect voltage.