The Indramat TBM 1.2-40-W1-024 is a high-performance bleeder module (braking resistor module) designed for use with Bosch Rexroth/Indramat AC servo drive systems. This module is essential for protecting the drive’s DC bus circuit by dissipating the excess regenerative energy generated during the rapid deceleration or braking of high-inertia servo motors. It effectively converts mechanical energy back into heat, preventing DC bus overvoltage faults.

 

⚙️ Technical Specifications

🔹 Model: TBM 1.2-40-W1-024

🔹 Series: TBM (Thermal Bleeder Module)

🔹 Voltage Rating: Optimized for standard Indramat AC drive DC bus levels

🔹 Peak Braking Power: 40 kW

🔹 Cooling Method: W1 (Internal convection/designed for integration)

🔹 Weight: Approximately 4.5 kg

🔹 Operating Temperature: 0°C to 45°C (Ambient)

🌐 Communication & Electrical Configuration

The TBM module does not require complex digital communication; rather, it is configured via electrical connections to the drive’s DC bus:

1. DC Bus Link: Connect the DC+ and DC- terminals of the TBM module directly to the intermediate circuit (DC bus) of the servo drive using appropriately rated power cables.
2. Thermal Monitoring: Connect the potential-free contact (ready/fault signal) to the servo drive’s digital input. This allows the drive to detect if the bleeder module is overloaded and shut down before thermal damage occurs.
3. Cable Sizing: Use shielded, high-current power cables to minimize electromagnetic interference (EMI) and ensure efficient energy dissipation.

 

⚡ Power-Up & Debugging Workflow

1. Pre-Power Inspection: Verify that all cable connections are tight. Ensure there are no short circuits between the DC bus terminals.
2. System Power-Up: Apply power to the servo drive. Monitor the drive’s DC bus voltage via the diagnostic interface; it should remain within the nominal operating range.
3. Deceleration Test: Perform a controlled deceleration command on the motor. Observe the bleeder module’s behavior; during high-intensity braking, the module should effectively clamp the DC bus voltage.
4. Fault Analysis: If an “Overvoltage” error occurs on the drive, verify that the TBM module is receiving the DC bus voltage and that its internal thermal switch has not tripped.

 

✅ First-Time Operation Checklist

• Ensure the TBM module is mounted vertically with sufficient clearance for heat dissipation.
• Validate that the peak braking energy of the application does not exceed the 40 kW rating of the TBM 1.2.
• Confirm that the drive parameter settings (specifically deceleration ramp times) are optimized to avoid triggering continuous bleeder overload.
• Check for “Brake Resistor Overload” signals in the drive diagnostics during the first full production cycle.
• Verify that the thermal monitoring contact is wired correctly to trigger a drive-stop in the event of a fault.

 

❓ Common Questions & Answers

Q: Why does my drive show a DC bus overvoltage fault during braking? A: This typically indicates that the TBM module is either not connected correctly, the internal fuse is blown, or the regenerative energy exceeds the module’s rated capacity for the deceleration ramp.

Q: Is the TBM 1.2-40-W1-024 hot-swappable? A: No. Always ensure the DC bus is fully discharged (verify with a multimeter) before disconnecting or replacing the bleeder module.

Q: Can I use this module with non-Indramat drives? A: While the principle of DC bus clamping is universal, the TBM series is specifically tuned for Indramat/Rexroth voltage thresholds. Using it with other brands is not recommended without verifying compatibility.

Q: How do I know if the internal bleeder resistor is damaged? A: You can measure the resistance across the DC bus terminals (with power disconnected). An “Open” reading indicates a blown internal fuse or failed resistor element.