| 摘要 |
A fan operating system includes inlet vanes adjustable to vary the angle of introduction of air into the fan and an induction motor speed control able to operate the motor at a speed in excess of the predetermined standard (synchronous) speed for the motor based upon mains frequency and the number of poles. For operating in accordance with square law duty requirements the inlet vanes are fully open and the motor speed is selectable to a speed of below the predetermined synchronous speed, whereas outside the square law demand regime the inlet vanes are less than fully open and are adjustable while the motor is operated at a speed higher than its synchronous speed. Such a system can be used to operate in and outside a square law demand regime. |
