Henry Ford once said, “Quality means doing it right when no one is looking.” Sound motor management practices, like conducting a motor inventory to assess repair-replace decisions before motors fail, are done behind the scenes, but can lead to noticeable energy and cost savings. The right management practices enhance the quality of your operational processes, and serve to make your plant more lean and efficient.
As you practice motor management, don’t overlook the value of assessing other equipment connected to your motor. Motor-driven systems can include adjustable speed drives (ASDs), interfaces such as belts and the driven load, for example, as well as pumps, fans, etc. As the following example shows, managing motor-driven systems yields significant process improvements, energy savings and quality.
Rubber Manufacturer Extrudes System Savings [Ref. 1]
An industrial rubber manufacturer found an energy savings opportunity through assessing their motor-driven system. In this case the motor system included a 1500 hp motor controlled by an electromagnetic, eddy-style clutch, which powered an extruder. By replacing the clutch with a variable frequency drive (VFD), the manufacturer was able to achieve process improvements, energy savings, reduced maintenance costs and improved power factor for the entire plant.
The 24-pulse frequency drive saves more than 1.3 million kilowatt-hours per year, which adds up to over $40,000 in utility-bill savings. After the project, analysis revealed that 40% of the extruder’s electricity consumption was previously wasted using the clutch controller.
Additionally, the installation of the VFD improved operations and maintenance in the plant. The VFD also increased the precision of speed control, allowing for better extruder operations. Additionally, the VFD installation increased the space around the extruder that was previously occupied by the clutch, impro-ving the effectiveness and reducing the cost of extruder maintenance.
Working with its local utility on this project, the plant realized a 5.75-year simple payback on investment, based only on electricity savings. Other returns on investment, including labor, product quality and power-factor benefits further reduced the project’s payback time.
As this example shows, significant process improvement and energy-saving opportunities are the reward for sound motor system management. When it comes to assessing your system’s potential, find information on successful application of drives in the NEMA Application Guide for AC Adjustable Speed Drive Systems [Ref. 2]. To learn more about building on the basics of motor management by considering system savings with drives, visit the MDM VFD Resources Webpage [Ref. 3] that provides links to resources such as VFD savings calculators and additional case studies.LMT