Product Description:

The RZW03.1-003-040 braking resistor is produced by Bosch Rexroth Indramat as part of the RZW Braking Resistors series. In an automation line, it connects to the DC bus of an inverter or servo drive and dissipates regenerated energy as heat, keeping the bus voltage below the drive’s threshold during rapid deceleration or overhauling loads. By handling this thermal work externally, the component protects transistor stages, shortens stopping distances, and supports repeatable braking profiles without adding active control electronics.

The resistor’s continuous power rating is 3 kW, so it can convert that amount of electrical energy into heat during each applicable duty interval. Its fixed resistance of 68 Ω sets the braking current that flows for a given DC-link voltage; lower values would raise the current but are not permitted because the minimum connectable resistance is 30 Ω. An operating factor of 40% SD means the unit may conduct for 40% of each specified load cycle before reaching its permissible temperature. The IP23 protection class guards against contact with hazardous parts and exposure to spraying water when the device is mounted vertically inside a cabinet. Wiring enters through two screw lugs, and the two terminals accept a 2.5 mm² supply conductor, while the separate protective-earth stud requires a ground lead of at least 10 mm². The aluminum housing measures 335 mm in height, 230 mm in width, and 182 mm in depth, allowing sufficient panel space and airflow clearance.

The resistor has a thermal time constant of 150 s, which indicates how quickly its temperature rises or falls after load changes. A complete load cycle lasts 120 s. Within that period, the resistor may conduct continuously for up to 48 s and then must remain off for at least 72 s to cool to its reference temperature. The 7 kg assembly provides enough thermal mass to absorb heat without exceeding its operating limits while remaining suitable for panel mounting.