Product Description:

The RZW03.1-055-015 dynamic braking resistor is produced by Bosch Rexroth Indramat for the RZW Braking Resistors series. Installed on the DC link of servo and inverter drives, it converts surplus regenerative energy into heat and prevents overvoltage trips in motion axes. The component follows mechanical design 1, allowing direct installation on cabinet back panels or machine frames without extra adapters. Its resistive grid and finned enclosure rely on natural convection to remove heat during repetitive deceleration cycles.

The unit is rated for 55 kW during each duty sequence, based on a 15% operating factor over a 120-second load cycle. An internal resistance of 5.5 Ω sets the current drawn from the drive while energy is being dissipated. Field wiring should use conductors with a cross-sectional area of 35 mm² to limit voltage drop at peak current. The IP23 protection level shields the assembly from fingers, tools, and falling water while still allowing air to pass through the grille. The structure weighs 51 kg, and its 520 mm height provides ample radiating area for the vertical cooling channels. Factory-set bracket spacing supports consistent installation, and the resistor may conduct for 18 seconds followed by 102 seconds of idle time to keep average heating within its thermal limit.

A thermal time constant of 100 s indicates how quickly the housing approaches its steady-state temperature after a load step. Surface temperature is limited to 80 °C, so nearby components can use standard 90 °C insulation. The enclosure measures 795 mm in width and 490 mm in depth, providing a substantial surface area for passive heat dissipation. It mounts through M10 terminal studs that accept ring lugs for secure bus connections. When higher braking power is required, multiple units can be interconnected, provided that the combined resistance does not fall below the drive system’s minimum resistance of 5 Ω.