Drives: Getting a handle on whole-life costs
19 Nov 2007
Purchase price plays a crucial role in the use of drive equipment, yet in order to reap the greatest benefits and unlock the real value from equipment, plant managers should be embracing the concept of whole-life costs. The potential rewards for the whole-life costs approach can be greater machine availability, higher productivity levels, greater energy and machine efficiency, as well as lower maintenance costs.
The process involves calculating the expenditure of a system throughout its entire life, and then calculating and comparing the impact of alternative products. For this, it is important to know the accrued cost of a product over a period of time, addressing a range of issues such as energy costs, maintenance changes, installation time and cost, as well as the effect of various environmental factors.
The calculations are not only useful for forecasting the lifetime cost of equipment but also for monitoring current situations. In some circumstances, this has presented a significant hurdle for companies due to reluctance to provide all of the necessary/required information for an accurate assessment.
Energy consumption is a key factor for the process industry as prices continue to remain unstable. Systems and equipment with the capability to reduce consumption levels are therefore of key importance
In many traditional systems, the braking system presents an area of high maintenance due to the constant ramping up and down of the load. The process traditionally occurs via mechanical or electrical means and therefore requires regular maintenance checks and servicing approximately every three-to-six months to prevent failure. For such applications, variable speed drives, which can offer highly efficient regenerative braking, provide substantial advantages.
Furthermore, for many businesses the cost of potential downtime can be a huge expense and must be prevented and managed where possible. Proactive maintenance should, therefore, be a priority factor in the purchasing decision.
Many companies continue to view maintenance as purely a cost factor, but do not budget it into the whole-life cost of equipment. After energy, maintenance represents the next largest expenditure in plant, costing as much as 12.5% of revenue and often therefore exceeding profit margins.
Predictive maintenance is one potential solution as it assesses whether equipment will fail in the future so that businesses are able to take the necessary action to avoid the consequences. This process of the plant operation system rather than just maintaining assets and attempting to restore equipment to its original condition.
Retrofitting equipment is another option. Rather than simply replacing manufacturing equipment like-for-like, retrofitting offers benefits including efficiency and cost, as well as operational gains such as maintainability, connectivity, improved diagnostics and reduced downtime.
