The VW3A58704 is a braking resistor from the Altivar range, designed for use with Altivar 31C variable speed drives. It provides a 68 Ohm resistive load to dissipate regenerative energy from the DC bus during deceleration, rated at 28 W continuous at 50 °C ambient and 32 W at 40 °C.
Dimensions are 170 mm height, 60 mm width, and 30 mm depth, suitable for DIN-rail or chassis mounting with adequate clearance for heat dissipation.
The unit is unprotected (no over-temperature or overcurrent protection built in), so the drive's braking transistor and control logic must manage the duty cycle to prevent thermal overload.