Danfoss VLT Error Code 2563: Brake Resistor Shorted Error code 2563 on a Danfoss VLT frequency converter indicates a specific hardware fault regarding the brake chopper and resistor circuit. The drive has detected a short circuit in the brake resistor or the cabling connected to the brake terminals. Here is a detailed breakdown of the error, its causes, and how to troubleshoot it. 1. Fault Definition
Error Code: 2563 Name: Brake resistor shorted Description: The frequency converter has detected a short circuit across the brake resistor terminals (typically terminals UDC- and R-). This is detected during the drive's power-up self-test or during operation.
2. Common Causes This error is almost always caused by a physical issue in the braking circuit. Common causes include:
Physical Short Circuit: A loose piece of wire, copper strands, or debris bridging the terminals inside the drive or at the resistor connection point. Damaged Insulation: The insulation on the brake resistor cables has worn through (e.g., rubbing against the cabinet frame), causing a short to ground or between the wires. Failed Brake Resistor: While resistors usually fail by going "open circuit" (breaking the connection), they can occasionally fail internally in a way that creates a short, or the thermal protection switch inside the resistor may have tripped and shorted. Moisture/Contamination: Water entry or excessive conductive dust inside the terminal box of the brake resistor or the VLT drive. Incorrect Wiring: The resistor wires may be connected to the wrong terminals, effectively creating a short. Danfoss Vlt Error Code 2563
3. Troubleshooting Steps ⚠ WARNING: High Voltage. Ensure the drive has been disconnected from power for at least 4 minutes (or as specified in the manual for your specific VLT model) to allow the DC link capacitors to discharge fully before working on the terminals. Step 1: Visual Inspection
Remove power from the drive. Locate the brake resistor terminals. On most Danfoss VLTs, these are terminals R+ and R- (or UDC- and R- depending on the frame size). Look for loose wire strands, debris, or signs of burning/arc flashing between the terminals.
Step 2: Disconnect and Measure
Disconnect the brake resistor cables from the VLT drive completely. Use a multimeter to measure the resistance between the two cables coming from the resistor.
Expected Result: You should read the rated resistance of the resistor (e.g., 20 Ohms, 50 Ohms). Check the resistor label for the correct value. Short Circuit Result: If the multimeter reads close to 0 Ohms (or very low), the resistor is internally shorted and must be replaced.
Measure continuity between each resistor cable and the ground/earth. There should be infinite resistance (OL). If there is continuity to ground, the cable insulation is damaged. Danfoss VLT Error Code 2563: Brake Resistor Shorted
Step 3: Check the Drive Internals
With the resistor disconnected, measure the resistance between the drive's brake terminals (R+ and R-). If the drive terminals show a short circuit (0 Ohms), the internal brake IGBT (chopper) module may be damaged, requiring repair or replacement of the power card/drive.