What is the critical speed of the fan?
More than this speed after the amplitude increases with the speed gradually reduced, and stable in a certain range, the rotor maximum amplitude of the rotor speed is called the critical speed
When the speed is equal to 2 times the natural frequency known as the second order (level) critical speed, followed by analogy third order, fourth order ... ... can be calculated according to the formula!
This speed is equal to the natural frequency of the rotor, when the speed continues to increase, close to 2 times the natural frequency amplitude will increase,
Fan rotor in the operation will occur in the vibration, the rotor amplitude increases with the increase in speed to a certain speed to reach the maximum amplitude (that is, usually said resonance)
