Causes of Belt Failure and Power Loss
Reason of belt failure
Weak design - Poor design is the leading cause of slipping off and vibration of the belt. Long belt drive absorbs vibration and shock on them and protects the machine elements from failure.Misalignment and improper installation - V-belts are protected from slipping off by wedging action of grooved pulleys. While flat belts are placed on pulleys without grooves, this increases the chance of slipping. Crowning of pulleys can resolve it.
Misalignment increases the chance of slipping off of the belt. That also leads to uneven stress on the belt and causes excessive wear.
Poor Maintenance and cleaning - The system must undergo regular maintenance. Cleaning is essential; otherwise, the debris of wear on pulleys and belt makes the case worse.
Internal defects - The belts may cause an internal defect; for instance, there may be broken individual cord in wire rope. If this defect not located it might cause sudden failure; increase in breakdown time is the effect.
Environment condition - Operation condition (temperature, dust, moisture, etc.) will affect the overall performance of a belt drive.
Reason of power loss in the belt drive
- Under pretension - Belt drives are pre-tensioned to increase grip and then reduce the slip. Slipping affects badly on velocity ratio and power transmission capacity.
- Creep - Change in length during a belt pass over through the pulleys due to uneven tension on the belt at upper and lower side.
- The friction of the pulley bearing.
- Aerodynamic resistance - It is negligible for the small belt drive.
- Slip - slip is unavoidable, even after good design, proper alignment and pretension. However, Timing Belts are free from the slip.
Belt drive - Types, advantage and disadvantage
Desirable properties of belt drive materials