(1) "Cross Flow Fan" for the same conditions, the higher the speed, the more prone to surge, the surge cycle is longer. Surge occurs, the indication of stability at high speeds, but its value is too small, then the internal fan heavy "surge" dull noise; when the speed is reduced, the indication of instability and great change, in the same period, the internal fan to "breathe" after "vibration", then alternate with each other. "Oscillation" phenomenon is the indication of a substantial increase in belt shaking intensified, vibration testing system means relatively strengthened by the dull to sharp noise;
(2) "Cross Flow Fan" same speed under different conditions, the smaller the resistance, that is, when the larger area of the vent, the more prone to surge phenomenon;
(3) "Cross Flow Fan" for the same conditions, a high speed when the surge, the real and the ideal normal deviate greatly, but compared with the low-speed stable value is not very different.