A pre-charge resistor fault in an Inovance MD200 drive indicates a problem with the component responsible for safely charging the DC bus capacitors during startup. This fault can prevent the drive from starting or cause erratic behavior.

Common Causes

• Resistor Failure: The pre-charge resistor itself may have failed due to aging, overheating, or other factors.
• Connection Issues: Loose or corroded connections to the resistor can disrupt its function.
• Drive Internal Fault: A fault within the drive's internal circuitry can affect the pre-charge resistor's operation.

Troubleshooting Steps

1. Check the Pre-Charge Resistor:

   • Visually inspect the resistor: Look for signs of physical damage, such as burns or discoloration.
   • Measure the resistance: Use a multimeter to measure the resistance of the resistor and compare it to the specified value in the drive's manual.
   • Replace the resistor if necessary: If the resistor is damaged or has the wrong resistance, replace it with a new one of the correct value.

2. Inspect Connections:

   • Check the connections: Ensure that the connections between the pre-charge resistor and the drive are tight and free of corrosion.
   • Clean the connections if necessary: If the connections are dirty or corroded, clean them with a contact cleaner.

3. Verify Drive Internal Components:

   • Check for internal faults: If the pre-charge resistor appears to be functioning correctly, there might be a fault within the drive's internal circuitry.