Motor-Operating Strategies Deliver More Than Just Energy Savings

In the industrial sector, cost is often the driving force when evaluating capital projects. However, plant owners and operators should be cautious of this approach and consider more than initial costs. The lowest-priced component is often the least cost-effective option. Instead, plant owners should develop a strategy for sustainability, which is the greatest opportunity and challenge that industry faces today. While significant barriers to change exist, adopting sustainable practices is vital to the long-term survival of most operations. This article discusses a sustainable approach to purchasing, repairing and upgrading equipment, whether it is part of a capital project or a motor replacement.

Developing a Strategy

For the U.S. industrial sector to remain competitive in the global market, experts must look to sustainable growth to achieve bottom-line savings. Short-term solutions are not the answer. Energy savings is considered by many to be the most significant opportunity for companies to reduce their operating costs. However, downsizing and investing in state-of-the-art manufacturing equipment will only go so far. While reducing energy consumption has a long-term impact, the challenge of implementing a savings plan often requires a change in attitude and leadership. Plant owners and operators must look beyond energy savings and learn to attach dollar values to non-energy benefits to achieve better bottom-line results.

Sustainable Solutions

One plant decided to solve pump failures and reduce maintenance costs by changing how motors were started and operated. Key to the success of the project were business managers who asked the right questions about the condition of equipment, history of failures and costs of downtime. The savings the plant recovered included reduced downtime and lost production from failures, in addition to the immediate savings from using less energy. The plant, built in 1972, experienced daily system load swings. The system included two operating vertical pumps (700 horsepower, 1,750 rpm) and one spare. The typical mean time between repair was four years. The industry standard, according to the Hydraulic Institute, is 10 to 15 years. The plant began experiencing frequent pump failures on Unit 2B. The unit failed nine times during the last four years, resulting in significant losses from downtime. The plant planned a 12-hour “outage window” during which the pump and motor were replaced. During that time, the installation and repair team implemented several solutions to relieve problems such as pipe stress, misalignment and incorrect startup and operating procedures. The sole plate was leveled after personnel discovered that it was out of level by 0.2 inches at the pump mounting surface. The coupling was replaced, and the 0.6-inch pipe stress at the stuffing box was relieved. Before startup, the system was vented to prevent water hammer. Afterward, the team decided that the plant should operate only one pump until the system could support a second pump within an acceptable operating range. The system is controlled with a main recirculation valve, but it is also a good candidate for variable speed control at the motor rather than bypassing back to the hot well. Because of these solutions, the system has run without failures since 2000.

The Bottom Line

The team successfully made a business case for sustainability. The plant was able to improve the bottom line and run a more sustainable operation while still eliminating failures, downtime and lost production. After calculating the cost and frequency of repairs, the potential savings for the plant was about $1.5 million across 30 years or about $50,000 per year. Because the primary problem involved startup and other operational procedures at the motor, the repair costs were low compared with the potential savings—about $7,000. As this team’s experience shows, owners and operators must look beyond energy savings. Improved reliability, reduced maintenance costs and increased productivity will allow process industries to reduce the cost of doing business. For today’s manufacturers, the cost of doing nothing is too great.