The Square D VW3A16705 is a dynamic braking resistor designed for use with the Altivar 16 series of variable frequency drives. Its job is to absorb regenerative energy from a decelerating motor, converting it to heat so the drive's DC bus does not overvoltage and trip out.
The VW3A16705 is a resistor-only module; it mounts externally to the Altivar 16 drive and connects via the drive's dedicated braking terminals. No additional control wiring is needed — the drive's internal braking transistor switches the resistor in during deceleration. Verify the resistor's ohmic value and power rating match your drive frame size and duty cycle; the wrong value can either fail to absorb enough energy or overcurrent the transistor.