"Cross Flow Fan" centrifugal cooling fan during the test, should carefully read the product manual, check the wiring method if the same wiring diagram is consistent; should carefully check the supply fan power supply operating voltage is not meet the requirements, whether the power phase or same phase, the distributor element of capacity to meet the requirements. When two-speed centrifugal cooling fan test, you should start low, check the direction of rotation is correct; must be stationary when starting the fan speed and then start to prevent high-speed reverse rotation, causing damage to the motor and switch tripping.