LUST LTI Drives BR-200.02.540.UR Braking Resistor

The LUST LTI Drives BR-200.02.540.UR is a braking resistor designed for industrial drive systems. It is rated at 150 W continuous power and 200 ohms resistance. The ALW80 designation refers to the housing type. The resistor is connected to a braking chopper or braking module so that regenerative energy produced during motor deceleration is converted into heat and dissipated safely. This protects the DC bus from overvoltage and maintains stable drive operation.

Function and Purpose

When a motor decelerates a high inertia load or a vertical load, energy returns to the DC bus. Without a means of dissipation, the bus voltage rises and can trigger an overvoltage fault. The braking resistor provides a controlled path for this energy. The braking chopper monitors the bus voltage and connects the resistor when the voltage exceeds a threshold. The resistor then converts the excess energy into heat until the bus voltage returns to a safe level.

Model Identification

The model designation BR-200.02.540.UR identifies the resistor type and its main electrical values. The 200 value indicates the resistance in ohms. The 02 field may refer to the power class or construction series. The 540 value defines the maximum voltage rating. The UR suffix describes a specific mounting or connection variant. The ALW80 housing provides mechanical protection and a defined thermal path for heat dissipation.

Electrical Characteristics

The resistance value determines the braking current at a given bus voltage. A lower resistance produces a higher braking current and therefore a higher braking power, but it also increases the load on the braking chopper. The 200 ohm value is chosen to match the chopper and the DC bus voltage of the drive system. The 150 W continuous rating defines how much power can be dissipated over time. For short braking events, the resistor can absorb higher peak power within the limits of its thermal time constant.

Thermal Behaviour

The resistor generates heat during braking. The ALW80 housing is designed to transfer this heat to the surrounding air and to the mounting surface. Adequate clearance is required to allow air circulation. In applications with frequent braking, the duty cycle must be calculated so that the average power remains within the continuous rating. If the duty cycle is high, a larger resistor or forced ventilation may be required.

Installation Guidelines

Mount the resistor on a metal panel or in a ventilated area of the cabinet. Keep it away from temperature sensitive components such as capacitors and control electronics. Connect the resistor to the braking chopper using cables sized for the maximum braking current. Tighten terminals to the specified torque. Ground the housing according to local electrical codes. Provide protection against accidental contact because the surface can reach high temperatures.

Protection and Safety

The braking circuit should include protection against short circuit and overload. The braking chopper monitors current and temperature and will shut down if limits are exceeded. A thermal switch or fuse may be used to protect the resistor in the event of a fault. The resistor housing must be grounded and the wiring must be protected against mechanical damage.

Applications

The BR-200.02.540.UR is suitable for applications with frequent braking, high inertia loads, or vertical axes. Examples include cranes, hoists, elevators, winding machines, and centrifuges. It is also used in machine tools and production lines where rapid deceleration is required. In multi-axis systems, the braking resistor helps stabilise the DC bus and improves overall system efficiency.

Maintenance and Service

Inspect the resistor periodically for signs of overheating, discoloration, or damage. Check terminal tightness and cable condition. Clean dust from the housing and ensure that cooling paths remain open. Verify that the braking parameters in the drive match the resistor rating. Keep a record of braking duty and fault history to detect changes in machine behaviour.

Selection Considerations

Calculate the maximum regenerative energy and the required braking power. Select a resistance value that matches the braking chopper and the DC bus voltage. Confirm that the continuous power rating is sufficient for the expected duty cycle. Consider ambient temperature and cabinet cooling. Verify that the housing type and mounting arrangement suit the installation.

Conclusion

The LUST LTI Drives BR-200.02.540.UR is a 150 W, 200 ohm braking resistor in an ALW80 housing. It provides reliable dissipation of regenerative energy and protects the DC bus from overvoltage. With correct selection and installation, it contributes to stable and efficient operation of industrial drive systems.