Model ND-RSD is a rectangular parallel blade damper constructed from heavy duty extruded aluminum with nylon bearings for quiet operation. The Motor Actuator is a 24 VAC (6 Watt /8VA) Synchronous motor. It is typically a Power Close / Spring Open construction. The damper can be ordered as Power Open / Spring Close. The Model ND-RSD cannot be field-reversed.
The Synchronous motor can get very warm when energized/stalled for extended time periods. To avoid overheating, do not insulate or encapsulate the motor housing. Doing so will damage the actuator assembly and void the warranty.