"AC Fan" centrifugal fan is the first to use it to start from the beginning. Cause sometimes fails to be started or the start time is very long question, the emergence of this situation are many. If the motor is not drag, just check the settings of the safety mechanism; if motor rated power is too low, replace the motor; if the program does not start correctly, on the adjustment of the starting device; if you start when power consumption is too large, it is verified when the starter whether the gas flow control mechanism in the closed position; if the rotor stuck, moving fans on hand to check the disc and investigation stalled Cause (friction, obstructions, etc); if too low voltage at the motor connection, you check the power line voltage - such as the loss is too large, increasing the power cord.