RZW03.1-037-006

Product Description:

Bosch Rexroth Indramat manufactured the RZW03.1-037-006. With a precise electrical resistance of 7.4 ohms, the Bosch Rexroth Indramat RZW03.1-037-006 brake resistor controls the current-voltage relationship according to Ohm’s Law directly. Resistance is the measure of how much a conductor hinders electron flow, mainly due to electron-lattice scattering in the metallic elements of the resistor. The current drawn during energy dissipation events is determined by this 7.4 ohm rating, which has to be matched precisely to the drive system’s voltage and braking needs. Too high a resistance will result in too little braking torque, and too low a resistance will cause too much current to flow and thermal and electrical risks. The motor and power electronics are protected from overload or instability by this delicate balance, and kinetic energy is safely and reliably converted into thermal energy during braking.

The power rating of the resistor – 37 kW in this case – is the measure of its thermal energy dissipation capability. This rating indicates the maximum power the resistor can absorb and convert into heat without exceeding its thermal limits. In real-world applications where regenerative energy from braking cycles is significant, this means the device can handle up to 37,000 joules of energy per second. The thermal design of the resistor is directly influenced by the power class, which determines the size of the heat sink, the material selection and the cooling features. Such a high rating is necessary to have safe thermal margins in systems that use high-frequency braking or large rotating masses. A zinc coating as a corrosion barrier is introduced during the galvanization process and is applied by hot-dip or electroplating process.

Zinc protects the underlying steel as it oxidizes first when exposed to moisture or corrosive substances, as it has a lower electrochemical potential than iron. This cathodic protection method ensures constant performance even in facilities with high humidity, chemical exposure or airborne particles by extending the life of the resistor in harsh environments. Through an integrated axial fan, the resistor uses external forced-air cooling to control internal temperatures during dynamic braking cycles. Unlike natural convection, forced convection uses mechanical airflow to keep the resistor surface and surrounding air at a sharp temperature differential, which accelerates heat loss. This allows higher power throughput without thermal overload and reduces the system’s thermal response time. A wind vane relay attached to specific terminals monitors the airflow. In case of cooling failure, this sensor-driven feedback device allows automated shutdown or problem reporting by confirming the existence and quality of the airflow.