Why Pakistani fans are noisy / not market comfortable then other countries fans

Why Pakistani fans are noisy / not market comfortable then other countries fans?
There are many reasons that Pakistani fans are noisy / not market comfortable then other countries fans. Pakistan is not able to meet the markets of first world because of many reasons such as deficiency of skilled labour, not a good infrastructure, inconsistent raw material, low level of production, inadequate technology, poor energy efficiency and unable to meet international certifications1. The first thing is that the material which used in Pakistani fan industries is of very low grade. Low grade material used in Pakistani fan industries to target low cost solution which consequently leads to an inefficient design. Material such as Drum sheet is commonly used as core material in Pakistani fan industry due to its low cost and accessibility. Drum sheet is made up of carbon steel containers which are mostly corroded due to oxidation process. In Pakistani fans induction motor is used but in foreign fans Permanent Magnet Synchronous Motor (PMSM) is used. The other reason is that in Pakistani fans induction motor is used. Induction motor operated at high slip and it decrease the performance of ceiling fan motor. But in foreign fans have no require electrical excitation because of PMSM. Induction motor requires more electrical power then the other motors. The designing criteria of induction motor for fan is not suitable. PMSM are more suitable for fan machine 2. Ball bearing is the important part that ensures smooth running and noiseless working of electric fan. But in Pakistan local ball bearings are used which have no good material 3. In foreign countries Electric Sheet Steel (ESS) is major item in fan manufacturing. In Pakistan Mild Sheet Steel (MSS) is used which do not give quality product and this product do not meet the international standards 3. The noise problem in Pakistani fans is also due to the difference in frequency in Pakistan and foreign countries. The high frequency decrease the noise but low frequency increase noise. In Pakistan electricity is 230 volts, alternating at 50Hz. In United States is 120 volts, alternating at 60Hz. Due to high frequency United States fans do not produce noise but in Pakistani fan due to low frequency produce noise 7. The noise in Pakistani fans is also due to design of blades of fan. The basic design of fan blades has changed little over the years. Currently there is no design set up related to fan blades in Pakistan fan industries 4. In Pakistani fans blades have linear sweep angle. However in foreign fans have non-linear forward sweep angle 5. Blades bends are manually adjusted to improve air delivery and reduce the noise 2. Parker proposed a fan blade design with a positive twist at the blade root and rounded trip. This new design gives less vibration and less noise. But in Pakistani fans design of fan blades is different and they produce noise 6. There is another reason of noise in Pakistani fans is using of inefficient design techniques. This problem is due to the reason that the labour is not well trained from any technical institute and they not know about the new efficient design techniques 3.

References:
TDAP, Engineering Division’s Report on Pakistani fan industry. 2011: Karachi
Analysis of Fan Industry of Pakistan
Fan Industry of Pakistan, A Critical Analysis
M.A. Afaq, A. Maqsood, K. Pervaiz, A. Mushtaq ” Study on the Design Improvement of Indoor Ceiling Fan, 2014
E. Adeeb, A. Masood, A.Mushtaq, “Shape Optimization of Non-Linear Swept Ceiling Fan Blades through RNS Simulation and Response Surface Method”, 2015.