Braking Resistor for Altivar 71 Drives
The Schneider Altivar VW3A7809 is a braking resistor designed for the Altivar 71 drive series, rated at 1.8 Ohm with an average power dissipation of 30.6 kW at 50 °C. This component is essential for dissipating regenerative energy from the motor during deceleration, preventing DC bus overvoltage faults. The M10 bar wire connection provides a high-current path suitable for the power level, and thermal protection is handled by an external thermal overload relay — not integrated into the resistor itself, so the drive or a separate relay must monitor temperature.
Physical Integration and Environmental Limits
At 890 mm wide, 690 mm high, and 450 mm deep, this resistor occupies significant panel or floor space. Operating ambient temperature range is 0 to 50 °C; storage range extends from -25 to 65 °C. The M10 bar wire connection requires a torque tool for secure termination, and the resistor body must be mounted with clearance for heat dissipation.