Causes and Countermeasures of cooling fan without wind

Causes and Countermeasures of cooling fan without wind


Maintenance of such failures, you can carefully listen to the wind wheel motor buzz, there are two cases:


(1) there is no buzz in the motor


1) broken power line, damaged plug, loose connection of electrical components and wires. The resistance between the power plug and the connection head is measured by the resistance gauge of multimeter. If the resistance value is zero, that is the path is intact; if the resistance value is infinite, it shows that the power line and the connection line are broken.


2) the speed switch is out of order. Lack of speed switch contact spring elastic contact piece, caused by bad contact, can clamp the upper contact piece will be slightly curved downward, but bent to open just perfect, the upper and lower contact points can be separated, when the normally closed contact can contact as well. The oxide layer on the contact surface is black and can be wiped off with fine sandpaper or eraser so that the metal surface of the contact is exposed.


(2) the motor has a buzz


There are two reasons for this failure: one is hand struck when the wind wheel rotation is normal, but the power does not turn, accompanied by sound, that mechanical transmission cooling fan and the rotating part is basically normal, fault reason for general motor stator winding open circuit or short circuit, capacitor failure etc.; another which is connected to the power supply, hand pull the wind wheel, handle rotation is not flexible, heavy, blocking phenomenon, and accompanied by a large AC electromagnetic acoustic fault, the main reason for the power supply voltage is too low, bearing wear or lack of oil, stator and rotor rub, the motor stator winding circuit, bearing clamp failure.


1) first use the multimeter  AC voltage to check the voltage of the city.


2) examination using direct method, to see if there is no obvious mechanical damage, such as wind wheel shell deformation and collision. If the wind wheel and the wind wheel rotation deformation can be blocked, the wind wheel removed, plastic deformation of parts, until the repair to the original shape, and then re assembled, the wind wheel and the shell should not collide.


In the power off state, the rotor shaft is rotated by hand, such as the half light and half weight of the hand, and then the first one is to check whether there is a foreign body obstruction in the rotor air gap. If there is a blockage in the air gap between the rotor and the stator, the motor should be removed to remove the foreign matter, so that the rotor does not block when rotating. If there is no foreign body, the rotor shaft should be checked whether it is deformed or bent. For rotor shaft deformation, bending, can be corrected, but also the overall replacement of the motor.


4) the rotor shaft is rotated by hand when the power is on, such as the heavy feeling of the hand, then the motor is checked to see if the oil bearing is lack of oil and is seriously worn out. If the bearing is worn out, as long as the oil bearing in the lower cover is removed and replaced by a new bearing, the fault can be eliminated. After installing the bearing, proper amount of lubricating oil should be injected.


5) check whether the bearing clamp is invalid. When the new bearing clip is installed, the bearing should be kept at about 5 degrees of swing under the influence of the spring force of the bearing clip, so as to meet the need of automatic adjustment in the assembly, but the bearing can not be rotated absolutely.


6) the capacitor works under high voltage for a long time. If the capacitor is "bulging", that is, the capacitor fails, the new capacitor with the same size (1.2 F 5%500V) should be replaced.


7) the stator winding open circuit or short circuit of the wind wheel motor is one of the easy faults of the motor. Check the magnitude of the DC resistance of the winding and the on-off condition with the multimeter to judge whether the motor is damaged or not.