| 摘要 |
On the fan (4) blade (9) is fitted an elasticity indicator (10), the output of which is connected to the input of a primary amplifier (12). A unit is employed for investigating the vibration resonance frequency of a fan blade, and has its input coupled to the output of the primary amplifier. A second unit maintains the fan blade vibration resonance frequency constant, and has its input coupled to the outputs of the first unit, whilst its output is connected to the input of the control unit (8). The first unit incorporates the following series-coupled functional units: a two half-period rectifier, the input of which is coupled to the output of the primary amplifier (12), a compensating filter, a differentiating unit, a zero detector, and a first power switch. The functional units of the second unit are an air flow pressure gauge fixed to the fan blade, a secondary amplifier, a first rectangle impulse former, a phase detector, the output of which is coupled to the first input of a comparative unit, and through a switch to the input of a memory unit. |
