Regenerative Transistor Fault

What does rr mean?

This fault indicates an issue with the regenerative braking transistor or its control circuit within the inverter. The regenerative transistor is responsible for dissipating excess energy from the motor during deceleration into a braking resistor. A fault here means the inverter cannot safely handle regenerative power, which can lead to overvoltage trips or damage to the DC bus capacitors.

• Internal damage or failure of the IGBTs (Insulated Gate Bipolar Transistors) within the regenerative braking circuit.
• Short circuit detected in the external braking resistor or its connecting cables.
• Braking resistor value (Ohms) is too low or its power rating (Watts) is insufficient for the application's regenerative energy.
• Excessive or prolonged regenerative energy dissipation requirements exceeding the transistor's capacity.
• Faulty gate drive circuit for the regenerative transistor within the inverter.

Click steps to track your progress.

1. 1

   1. Disconnect the external braking resistor (if present) and measure its resistance (Ohms) to ensure it matches the inverter's specification.

2. 2

   2. Measure the insulation resistance of the braking resistor cables to ground using a megohmmeter (e.g., 500VDC test voltage).

3. 3

   3. Inspect the inverter's internal braking transistor module (if accessible) for visible signs of overheating, charring, or physical damage.

4. 4

   4. Verify parameters related to regenerative braking (e.g., Parameter C2-01 for resistor capacity, C2-02 for duty cycle) are correctly set.

5. 5

   5. If an external braking unit is utilized, check its power supply, input signals, and any fault status indicators on the unit itself.