The Gamma Supply Ultra EC Series of mixed-flow roof units can
  be used for supplying fresh air to an air handling unit or to an air
  conditioning system. They incorporate the latest state of the art,
  energy saving EC motor technology and are most efficient where
  conditions vary during the course of the day.
They feature integrated infinitely variable speed control and
  eliminate the need for external VSDs, current overloads and
motor phase protection.
The Gamma Supply Ultra EC Series is a simple “plug and play”
  system which means installers do not need to have specialised
control programing knowledge.
Matching sensors can easily be connected to monitor the
  ambient conditions in a space and provide real time feedback to
  the fan. The fan’s on-board microprocessor can adjust the speed
  and therefore modulate the ventilation rate to match the specific
requirements of the area.
They are available in 3 sizes extending from 450 to 560mm
diameter.
 
                            
                Motor
                Type - electronic commutated (EC) motor.
Electricity supply
  - 200-277V single-phase, 50/60Hz for 450mm size.
  - 380-480V three-phase, 50/60Hz for 500 and 560mm
  sizes.
  Bearings - sealed-for-life, ball.
Integrated EC Controller providing infinite speed control.
              
             
            
                Internal Protection
                Type - electronic commutated (EC) motor.
Electricity supply
  - 200-277V single-phase, 50/60Hz for 450mm size.
  - 380-480V three-phase, 50/60Hz for 500 and 560mm
  sizes.
  Bearings - sealed-for-life, ball.
Integrated EC Controller providing infinite speed control.