What effect does increased belt tension typically have on vibration characteristics?

Increased belt tension generally leads to a rise in vibration levels at the running frequency. This occurs because a tighter belt can transmit power more effectively, but it can also amplify vibrations in the system due to the increased stiffness and reduced damping characteristics associated with higher tension. When tension is increased, the resonance and vibrational response of the connected components can become more pronounced, particularly at the frequency at which the system is primarily running. This is often observed in mechanical systems where belt-driven components are involved, as the transmission of energy through a tighter belt can lead to greater excitation of the system's natural frequencies, thus resulting in higher overall vibration levels at those frequencies.

In contrast, decreasing all vibration frequencies would imply a reduction in the system's overall vibrational response, which is not typically the case with increased belt tension. Similarly, stating that there is no effect on vibration levels overlooks the connection between belt tension and vibrational characteristics. Lastly, asserting that only harmonic frequencies are increased does not capture the full impact that changes in belt tension can have across the spectrum of vibrational responses, as the running frequency is the primary concern in this context.