Air Conditioner Fan

The air-conditioning fan is a new type, of energy-saving, high-efficiency, variable-speed, low-noise centrifugal fan. This type of fan has a compact structure, convenient installation, small volume, large air volume, high pressure, and low vibration. Equipped with a three-phase voltage regulator or frequency converter, it can implement step-less speed regulation, especially suitable for ventilation places with strict noise requirements and a large range of air volume changes. It is an ideal supporting product for air conditioning, purification, and other industries.

DKT air-conditioning fans are suitable for various sizes of air-conditioning boxes, fan cabinet air-conditioning units, central air-conditioning units, and various purification equipment purchased and installed in industrial and mining enterprises, hotels, large shopping malls, and other buildings. It has the characteristics of strong versatility, high efficiency, low noise, and large air volume. No spontaneous combustion, no corrosive gas, the gas dust content, and other solid content are less than or equal to 100mg/m3, and the temperature is -20℃-80℃.

Air-conditioning fan The air-conditioning fan is mainly composed of a casing, an impeller, an air inlet, and an outer rotor motor.

Casing: The whole is made of galvanized steel plate or high-quality cold-rolled plate. Its shape is smooth, heat-resistant, moisture-resistant, and durable.

Impeller: The forward multi-wing circular arc blade is riveted to the front disc and the middle disc. After strict dynamic and static balance correction, it ensures smooth operation, high efficiency, and low noise.

Air inlet: processed by the mold, the section parallel to the axial direction is streamlined so that the gas is smooth and the resistance is small.

Outer rotor motor: The two shaft ends of the motor are fixed on the air inlet, and the impeller is directly connected to the rotating casing of the motor, which reduces the transmission loss and improves fan efficiency.

The air volume adjustment methods of the air-conditioning fan include outlet (inlet) air valve adjustment, worm line air valve adjustment, inlet blade adjustment, dynamic wing adjustment, and rotation adjustment.

  1. Air valve adjustment (outlet/inlet/worm-line) The adjustment of the outlet air valve is to change the characteristics of the pipe network, not the characteristics of the air-conditioning fan. Because the method of artificially increasing the resistance of the pipe network is used to change the characteristics of the pipe network, the pressure drop is consumed in the additional resistance generated when the damper is closed, and the economical adjustment is poor. The inlet air valve is adjusted. When the piping is arranged on the suction side of the fan, the adjustment principle is the same as that of the outlet air valve. However, when the piping is arranged on the exhaust side of the fan, it changes the performance curve of the fan by changing the inlet state parameters (ie the inlet pressure) of the fan, so the adjustment is economical. The worm-line air valve adjustment is to change the characteristics of the fan by changing the outlet area of the fan. Compared with the reduction of the air volume, the power change is small, and the energy saving is not significant. These two kinds of adjustment can be used in all working conditions under the rated curve in principle and can make the surge point shift to the direction of a small flow, so they are widely used in air conditioner fans with fixed speed.
  2. Inlet blade adjustment The inlet blade adjustment is to adjust the blade to change the airflow direction of the suction impeller and change the performance curve of the fan.

KDW series forward multi-blade outer rotor low-noise air-conditioning centrifugal fan is a new product developed by us on the basis of absorbing domestic new technology. The fan is a double-inlet type structure, which has the advantages of compact structure, convenient installation, low vibration, low noise, and lightweight. Its technical performance index has reached or even exceeded some similar products in China, and it is an ideal supporting product for the air-conditioning, refrigeration, and ventilation industries.

  • Fan operating conditions
  1. Conveying medium

The conveying medium of KDW series fans is air and other gases that are not spontaneously combustible, non-corrosive, non-sticky, or non-adhesive, and the dust and particles contained in the medium are not more than 150mg/m3. The gas temperature generally does not exceed 40°C.

  1. State of gas

The data in the sample performance parameter table are the parameters in the standard state. At this time, the air state is: atmospheric pressure 760mmHg, temperature 20°C, relative humidity 50%, and its density is 1.2kg/m3. If the operating environment of the fan is not equal to the gas standard state, please contact us, and we will choose a suitable fan for you.

  1. Use environment

The temperature of the gas delivered by the fan should not exceed 40°C, and the altitude generally does not exceed 1000m.

  • Transportation, storage, storage

Before the fan leaves the factory, sufficient attention has been paid to the centerline correction and dynamic balance correction of the fan, and it is allowed to leave the factory after the operation is qualified. Therefore, care should be taken that the fan is not scratched or even deformed when it is transported to the customer’s site.

  1. Component inspection
  • Check whether the fan is damaged, or deformed and whether the paint is in good condition.
  • Check whether the parts and spare parts of the fan are mixed, or omitted and whether the quantity is the same before and after transportation.
  1. Hoisting and Handling
  • When lifting the workpiece with ropes and steel wire ropes, the ropes should be as long as possible, and the rigging points should be arranged reasonably to prevent the fan from being deformed. Even small deformations may cause a decrease in the accuracy of the dynamic balance, causing the fan to vibrate during operation.
  • Grease nozzles, etc. are easily damaged during hoisting. When installing rigging, full attention should be paid.
  • During the moving process of the equipment, there is a great impulse to the motor and impeller, so please note that the bearing should not be damaged.
  1. Storage
  • Before the fan is installed, the fan should be placed in a ventilated and dry place and checked regularly to prevent rust and damage.
  • During the storage period, crank the fan at least twice a month, at least 10 revolutions each time.
  • Fan installation and use
  • Installation overview
  1. Ventilator installation site

Please pay attention to the following points when selecting a fan installation site:

  • If the ventilator is in the open air, protective facilities should be provided to protect it;
  • The ventilator should be placed in a place that is convenient for management and monitoring;
  • The fan installed on the elevated structure should be installed in a structure that does not induce vibration.
  1. Fan installation space requirements

The following points should be considered when estimating the site area for installing the ventilator:

(1) Do not hinder the normal operation of other adjacent machinery and equipment;

(2) The ventilator can be repaired safely and conveniently;

(3) There should be enough space to remove the impeller.

  1. Various installation methods and requirements
  • Installation on the ground

Fans are generally installed on concrete foundations, but small fans with smaller models and smaller motor power can also be installed directly on the ground without a foundation. Even so, attention should be paid to the strength of the foundation.

  • Installation on the floor (high platform)

Full attention should be paid to the rigidity and strength of the installation area to avoid resonance when the fan is running, otherwise, reinforcement measures must be taken.

  • Fan installed in the box

In order to avoid the vibration of the fan caused by insufficient structural rigidity and strength, it is necessary to pay full attention to the strength of the installation frame. Especially when using anti-vibration materials such as anti-vibration rubber (spring), be sure to install the fan and motor on the same chassis.

  1. For hanging on the ceiling

Small fans can be simply hoisted with bolts. For medium-sized fans, the hoisting type should try to use welded frame structures to install fans and try to use ground foundations for installation.

  1. The installation requirements are as follows:
  • Before installation, the data on the nameplate of the fan should be checked in detail, and the power supply must be consistent with the data on the nameplate.

Avoid eddy currents when allowing airflow into the box.

  • The fan should not be installed vertically (the shaft is perpendicular to the ground). If necessary, please ask separately when ordering.
  • Before installation, all parts of the fan should be strictly inspected, especially the impeller, motor and other transmission parts of the fan should be carefully inspected. If any damage is found, it should be repaired.
  • During installation, the fixing screws of the feet should be tightened, and the lead wire of the motor should be connected to the control cabinet at the same time. The rotation direction of the fan should be consistent with the direction of the casing rotation direction. The weight of the ventilation ducts should not be added to the enclosure. There should be no abnormal noise during the test run of the fan.
  • Use of the fan
  1. The motor power used by the ventilator refers to the power required when the air outlet is fully opened in terms of specific working conditions, plus the due reserve. If the outlet or inlet of the fan is not connected to the circuit and is running dry without external resistance, the motor is also in danger of burning. For the sake of safety, a valve should be added to the outlet or inlet pipeline of the fan, the motor should be closed before starting, and the valve should be slowly opened after the normal operation until the specified working condition. Pay attention to the current of the motor not exceeding the specified value of the motor.
  2. In order to make the fan run safely, the user must install the motor phase loss protection device during installation.
  • Test

Carry out a test run according to the following procedure.

  • Inspection

The bolts and nuts should be locked evenly and symmetrically one by one; otherwise, if the parts are too tight or too loose, it will cause air leakage, noise, and vibration, which will cause shaft wear and bearing damage.

  • Crank

When turning the impeller by hand, please pay attention to whether there is any abnormal sound.

The presence or absence of the sound of contact and friction, the sound of touching foreign objects, etc.

  • Ventilation system
  1. Whether the components in the device are properly configured as required.
  2. Check whether there are foreign objects near the air inlet and outlet or inside the fan unit.
  3. Near the inlet and outlet of the fan, whether there are unsafe factors (such as things that are inhaled or blown down) when supplying or drawing air.
  • Electrical wiring
  1. Whether the system has shorted or easily broken connections.
  2. Carefully check the connections inside the terminal box.
  • Startup
  1. After confirming that the ventilation system, electrical system, and other machinery are in a normal state, the machine can be started. First, turn on the switch for 3 to 6 seconds and then turn it off to check its steering and whether there is any abnormal sound, vibration, etc.
  2. If abnormal conditions are found during instantaneous operation, check and correct the unit according to the above process, and then carry out a trial operation.
  3. Generally, the starting current of fans and motors is 5~7 times their rated current, and then gradually decreases. If the current drop speed is too slow, stop running and check the motor power supply system.
  • Run confirmation
  1. According to the indicated value of the ammeter, slowly adjust the adjusting door to make the opening and closing angle reach the specified position.

(1) Record the current and voltage values;

(2) Check the vibration, temperature, and sound of the bearing;

(3) Pay attention to the heating of the motor. Generally, the allowable surface temperature of the motor is not greater than 80 °C.

  1. Please pay attention to the following matters within a week from the start of the fan operation.
  • Rubbing of rotating part:

① The friction between the impeller and the inlet;

② The friction between the impeller and the casing;

  • Other

① Whether the foreign body is inhaled or not;

② Vibration of the fan body.

  1. The fan shall not increase the speed arbitrarily to change the performance parameters of the fan, otherwise, accidents may occur.
  • Fan maintenance
  • Fan maintenance must pay attention to the following points
  1. Regularly maintain the fan. If the bearing has abnormal noise, the bearing should be replaced. The outer rotor motor should be replaced with a special bearing for the low-noise motor. Always check whether the connecting bolts, tightening and flat keys are firm, so as to prevent the impeller from rubbing against the air inlet and the motor shaft from rotating, twisting the power cord, causing vibration and increasing noise.
  2. When loading, unloading, transporting and moving the fan, it is strictly forbidden to pull the motor lead. All parts of the fan must not be collided with or squeezed by hard objects, and should not be stacked in places where wet or corrosive items are stacked.
  3. Keep it clean to prevent debris from entering the inside of the fan, which will affect the normal use of the fan.
  4. During the operation of the fan, if abnormal noise or severe vibration is found, it should be stopped immediately, the power supply should be cut off to find out the cause, and the operation can be resumed only after the fault is eliminated.
  • Reasons and solutions for common faults of fans

Some faults may occur during the operation of the fan. The causes of the faults must be quickly identified and solved in time to prevent accidents. The common faults, causes, and solutions are shown in the table below.

Fault Name Cause Approach
Abnormal fan noise 1. The fan is deformed during transportation and loading and unloading.

2. The impeller support screw is loose.

3. Rolling bearing damage.

4. The set screw of the bearing seat is loose and the spindle is displaced.

The fan impeller vibrates violently.

1. Loosen the set screws on both sides, adjust the gap between the impeller and the air inlet on both sides, tighten the set screws, and repair the deformed parts of the fan;

2. Tighten the fasteners

3. Check and replace rolling bearings;

4. The impeller is re-balanced and corrected.

Fan vibration 1. The stiffness of the bracket is not enough to cause resonance.

2. The rotor is out of balance.

1. Reinforce the bracket

2. Rebalance

Motor overcurrent 1. The gate or throttle valve in the inlet and outlet pipes is not closed tightly when driving.

2. The flow rate exceeds the rated value or the air duct leaks.

3. The input voltage of the motor is too low or the single-phase power supply is cut off, and the three-phase input voltage is seriously unbalanced.

4. There is no forward and reverse rotation of the fan in the same unit.

Affected by the deterioration or failure of the parallel fan in the same space.

1. Check and close the inlet and outlet trachea gates or throttle valves.

2. Reduce the valve opening so that the flow rate does not exceed the rated value, and check that there should be no air leakage in the air duct.

3. When measuring three-phase voltage, it must be basically balanced.

4. Check the same unit to make sure that there is no reverse phenomenon.

5. All fans in the same unit must run at the same time.

The control cabinet switch tripped 1. The rotor part of the fan is stuck.

2. If the motor does not run for a long time, the bearing is rusted and the motor does not rotate.

3. The motor enters the water.

The control cabinet contractor has quality problems.

1. Troubleshooting to make the rotor run flexibly;

2. Regular bearing maintenance, and flexible operation:

3. Remove the accumulated water in the motor and re-insulate it;

4. Replace the contactor.

Low or no air volume 1. The regulating valve is closed.

2. There is no return air.

3. Fan reverses.

1. After the fan is running, slowly open the regulating valve to the rated working condition.

2. Clear the return air filter and normal return air.

3. Reconnect the wiring to make the fan rotate in the correct direction.

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