The POWERVENT (PV) series of direct drive centrifugal in-line duct ventilation fans consists of twelve model sizes 4", 5", 6", 8", 10" and 12.4" respectively. All models are designed for direct connection inline with standard diameter round ducting. Airflow performance values range from 108 cfm(PV-100) up to 942 cfm(PV-315x). All PV fan models incorporate a powerful external rotor motor that has been factory matched to a nonoverloading backward curved centrifugal fan wheel. This powerful combination enables the PV fans to deliver exceptional airflow performances against high static pressure typically found in ducted ventilation systems. All motors within PV fans are fully speed controllable using voltage or frequency control regulators.