1. Overtightened Belts
   Excessively tight belts can lead to frequent belt damage and overheating of the rear bearing, potentially causing bearing failure. This is also a primary cause of vibrations. If the rotor vibrates, resonance phenomena may occur.
2. Overloose Belts
   Loose belts reduce friction, causing slippage and rotational losses. This results in insufficient power transmission, preventing the fan from operating effectively.
   • Correct Installation Method: Press the middle section of one belt with your finger; the deflection depth should range between one and two belt thicknesses.
   • Deflection Formula:

     $$\delta =0.016L$$Where $L$ represents the center distance of the pulleys (in millimeters). Points A, B, C, and D of the belt should align with and remain parallel to the connecting lines.

3. Belt Selection and Uniformity
   • Always select V-belts of the same specification and batch. If there is any variation in length, ensure only belts of equal length are used.
   • Avoid installing belts with varying tightness, as this can overload certain belts, leading to accelerated wear and damage.
   • Mixing old and new belts is strictly prohibited.

Regardless of the type of V-belt used, confirm the pulley model and the number of grooves before installation to ensure proper fit and performance.