Reduced mechanical wear and mechanical shock by VFD

By using a variable frequency drive to control the acceleration, and in some cases the deceleration, of the driven equipment to acceptable rates, mechanical shock loading and wear to the equipment can be reduced or eliminated.

An example where this has been implemented is in overland conveyors where the torque applied to the driving pulleys is controlled to a given defined maximum value so that the maximum tension in the conveyor belt is limited. If the speed of the conveyor is also controlled so that the specific loading of the belt is limited and controlled, then the belt will run at much slower speeds during reduced throughput, leading to longer intervals between bearing replacements on pulleys and idlers.

In the case of pipeline pump control, the use of variable frequency drives to control the flow rate at start and stop reduces the incidence of water hammer thereby promoting long life of the pipeline installation and increasing the energy efficiency as the control valve is no longer required.

Other examples include any load that suffers a power reversal during normal operation as the impact loading on gear teeth due to backlash can be reduced to acceptable limits at any torque reversal.