1. Look at random files The random files of each fan include the instruction manual, product certificate, electrical circuit diagram and packing list. When purchasing, check the quantity and quality of the parts according to the packing list.
2. Look at the net cover and the fan blade for obvious deformation. On the assembled electric fan net cover, use a pen to point to the highest point of a fan blade, slowly move the fan blade, and the other several fan blades correspond to the nib. The distance should be very close, then turn the fan blades, pay attention to see if the rotation is light and flexible, and can stop at any position.
3. See if the control mechanism is flexible. The control mechanism includes speed control switch, timing knob, moving head switch, lighting switch, etc. These control mechanisms should be flexible in operation and reliable in contact. For the speed control gear, it is not allowed to have two gears connected at the same time or one gear cannot be pressed. Press the stop button and each speed stop button should be reset normally.
4. Look at the performance part of the performance fan fan head tilt and tilt angles flexible operation, locking firmly, adjust to the maximum depression angle or shake the head to the final position, the mesh cover must not touch the fan pillar. When the fan is running, the stability is good, it can't be dumped, and the angle of shaking should not be lower than 60-80 degrees.
5. Look at the startup performance Startup performance is an important quality indicator for electric fans. During the test, it should be adjusted to the slow speed, and when the rated voltage of the power supply is 85%, the voltage regulator will reduce the voltage of 220 volts to 187 volts to start the electric fan. The electric fan should be able to start from a standstill and operate normally. The shorter the time required for an electric fan to start from normal operation to normal operation, the better the starting performance of the fan motor.
6. Look at the running and speed regulation performance. After the power is turned on, the moving head switch will be rotated several times to check whether it is malfunctioning or the assembly is too tight. In this process, the mechanical transmission part of the fan should not have abnormal noise. When the electric fan is running at high, medium and low speeds, the motor and the fan blades should be stable, with low vibration and low noise. The fan should be shaken and stopped, and there should be no abrupt, stagnation and jitter. The difference of the speed of each gear should be obvious, and the larger the air supply angle, the better. When the electric fan stops, the axial clearance of the rotating shaft does not exceed 0.5 cm, and the clearance is too large, which causes axial turbulence and impact sound during operation.
7. See if the leakage electric fan is energized, if there is strong hemp inductance when the hand touches, test with the test pencil, the test pencil will also display light, and it can be judged that the casing leakage is not available.
8. Look at the continuous running performance of the electric fan. After the electric fan has been running continuously for 2 hours, if the surface of the outer casing is hot, the temperature is too high and cannot be used. Under normal circumstances, the surface temperature of the head casing is below 50 °C, and it will not feel very hot.
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