Brake Resistor Overheat

What does 7112 mean?

The brake resistor has overloaded and is experiencing excessive temperature. This condition indicates that the resistor is dissipating too much energy, potentially due to an incorrect braking cycle or excessive supply voltage, posing a risk of damage to the resistor and surrounding components.

• Braking resistor undersized for the application, leading to continuous excessive power dissipation.
• Deceleration ramp time (e.g., P11-01) too short, forcing frequent and heavy braking.
• Incorrect brake chopper activation voltage parameter (e.g., P20-03) set too high, delaying chopper activation.
• Mechanical fault in the driven load requiring continuous braking (e.g., brake not releasing fully, heavy descending load).
• Faulty thermal switch or sensor within the braking resistor unit providing feedback to the drive.

Click steps to track your progress.

1. 1

   Inspect the braking resistor for discoloration or visible damage indicating overheating. Allow resistor to cool before proceeding.

2. 2

   Measure the resistance of the braking resistor across its terminals (e.g., R+/R-) and compare to its nameplate value (e.g., 10 Ohm).

3. 3

   Verify drive parameters P11-01 (Deceleration Time 1) and P11-02 (Deceleration Time 2) are appropriate for the load inertia and cycle time.

4. 4

   Check brake chopper activation voltage parameter (e.g., P20-03) and ensure it is set correctly for the drive and application.

5. 5

   Monitor the brake chopper duty cycle and resistor temperature feedback (if available as a diagnostic value, e.g., r0030) during operation.