The DVC-P roof fans are driven by EC- external rotor motors, so called energy saving motors with high efficiency. The input voltage for single phase units can vary between 200 and 277V, for three phase units between 380 and 480V. All motors are suitable for 50Hz and 60Hz and from size 355 up to 630 suspended on effective vibration dampers. Motor protection is integrated in the electronics of the motor, no additional external motor protection device is needed. The DVC-P versions have integrated pressure sensors and the electronics are programmed for a pressure constant operation. Two potentiometers in the electronics allow for 2 set values (day/night), one additional contact for an external setting. Casing from seawater-resistant aluminum, base frame powder coated. Backward curved impellers manufactured from polyamide PA 6 for size 190 and 315. From 355 up to 630 impellers manufactured from seawater resistant aluminium.