| 摘要 |
A controller for operating a two-speed fan motor at one of two speeds and for selecting the appropriate speed in response to conditions such as a maximum and minimum duct static pressure in a fan unit having moveable inlet guide vanes for controlling air flow rates through the fan unit when employed in a variable air volume system. Position sensing switches are provided on the fan unit for indicating to the controller when the inlet guide vanes are in their preferred switching positions, which may be full open or full closed. The controller then selects one of the two fan speeds as appropriate within an operating deadband limit which serves to prevent undesirable changes of motor speed.
|
