Product Description:

Bosch Rexroth Indramat builds the RZK02.1-400-BW as part of the RZK Heat Exchangers series. The device is an integrated brake resistor and heat exchanger that attaches to Indramat drive cabinets. During regenerative braking, it converts surplus DC-bus energy into heat and transfers that heat to ambient air, keeping the inverter electronics within their allowable temperature range in continuous and pulse-duty industrial automation cycles. Because the resistor is built into a finned exchanger, no separate liquid circuit is required, and enclosure airflow remains uncomplicated.

Two resistor networks give a combined resistance of 2 x 1.6 Ω, setting the current that flows when the drive dumps energy into the module. Under steady cyclic loads, each network can dissipate 2 x 2.5 kW, which matches medium-frame servo axes that brake frequently during indexing. For very short surges, the assembly tolerates 2 x 370 kW for 0.1 seconds, preventing DC-bus overvoltage after emergency stops. The thermal mass and aluminum fins yield a thermal time constant of 14.3 s, so surface temperature rises over a short interval after an energy burst rather than instantly. Heat is removed by the exchanger core, which provides 2 x 5 kW of cooling capacity when cabinet airflow follows the recommended clearance rules.

The housing is rated at IP20, so it resists incidental contact but must be mounted inside a protected electrical cabinet. During operation, the external plates do not exceed 80 °C, allowing neighboring cables to retain insulation integrity. The assembly has a mass of 2 x 23 kg, and mounting space must account for a depth of 520 mm together with 100 mm below and 200 mm above for ventilation. Additional installation details include a brake line cross-section of 4 × 16 mm², a matching ground conductor size of 2 × 16 mm², and an overall frame envelope of 480 mm width by 365 mm height.