One of the main principles of power transmission is consistent lubrication. Shaft seals play a hugely important role in this. Imagine a situation involving a shaft-mount reducer – electric motor prime mover, driven by belts, motion controlled by a torque arm – with an improperly seated seal. A blown-out input shaft seal is a nightmare situation, necessitating an entire breakdown and reassembly, not to mention re-aligning and re-tensioning the belts.