Energy efficiency for drives and motors

18. April 2011 17:45

NEMA Premium motors can improve energy efficiency and reduce costs across the product lifecycle.

John Malinowski, Senior Product Manager for AC Motors at Baldor Electric, a member of the ABB Group, gave a presentation today titled: "Energy efficiency and beyond: Leveraging motors and drives for profits" Baldor always starts every meeting with its mission statement:

To be the best (as determined by our customers) marketers, designers and manufacturers of industrial electric motors, mechanical power transmission products, drives and generators.


Mr. Malinowski said this about Baldor: They sell value. 90% of what they make stays in the US.

Life cycle costs need to be the main consideration when purchasing motors; just 2% of the cost involves the initial purchase, while 97.3% is fuel costs (.7% for one rewind). To highlight this, Mr. Malinowski compared the overall cost of pickup and hybrid automobile, and the five-year operating cost. He then compared a hybrid auto to a 50 HP motor:
  • Annual use: miles vs hours
  • Efficiency: mpg versus %
  • Fuel/Energy cost: $/gal vs kWh

Annual operating cost is key to value. Baldor sells value.

Energy costs can be managed. Only 11% of companies have written motor specs, and 12% have rewind specs. 24% of facilities have not addressed energy consumption, so there is a lot of room for improvement. The US Department of energy has estimated annual savings for NEMA Premium efficiency motors: 62-104 billion kWh in electricity, and 15.3-26 million metric tons of carbon dioxide. However, just replacing motors on failure will take 15-20 years to complete.

US Department of Energy has some motor best practices to reduce costs and energy consumption:
  • Replace motors with NEMA premium motors
  • Improve rewind practices
  • Reduce system load: 5-60% in savings
  • Control motor speed: 30-80% savings
  • Upgrade component efficiency: 2-10% savings
  • Maintenance: 2-30% savings
  • Motor downsizing (right sizing)

In addition to US DOE best practices, Baldor recommends conducting plant motor surveys on several levels:

Basic - survey facility and inventory all motors, tag action on failure. John suggests motors that are running continuously for 2 or more shifts should be replaced immediately with NEMA Premium motors. Motors running for one shift should be replaced on failure with NEMA Premium motors.

Advanced - measure current draw on each motor to determine sizing Allows to "right size" motors for each application. This will increase efficiency and power factor, and reduce purchase price. Consider adjustable speed drive here or in Level 3 system analysis. By 'right sizing' the motor, the highest efficiency is 75-100% of rated load.

Systems - add adjustable speed drives on fans and pumps to control flow and save energy. Look beyond the motor at the application during the survey. Benchmark energy cost per item produced. Add adjustable speed drives on pump and fan applications. Process control can increase productivity.

In conclusion, Mr. Malinowski offered the following comments and suggestions:
  • Motor efficiencies are regulated in US, Canada, Mexico, and most of the world.
  • Control plant downtime and energy costs by managing motors.
  • Think of a system approach - all components from line to drive load should be selected for efficiency.
  • Energy costs will continue to increase, act now.

 

Comments (2)

agree with youAhmed HamdyTuesday, 19. Apr 2011 18:53

Excellent WordsAhmed HamdyTuesday, 19. Apr 2011 18:46

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