Consulting-Specifying Engineer - December 2008 - (Page 57)

Equipment Lifecycles How green is your motor? Consider lifecycle costs when selecting a motor for your facility. BY JOHN MALINOWSKI, Product Manager AC & DC Motors, Baldor Electric Co., Fort Smith, Ark. ith today’s rising gasoline prices, people are looking more closely at fuel efficiency (measured in miles/ gallon) than in the past. Great deals are available for full-size trucks. In Arkansas, for example, Dodge Ram Hemi four-doors are available for $18,995, a price lower than for a much smaller Honda Civic Hybrid ($22,600). The larger pickup has more room for five people, plus it can easily carry a payload or tow a trailer. But most folks just use the truck to commute to work. Let’s look at the lifecycle of these vehicles, starting with the operating costs for 15,000 miles of highway driving. The U.S. Environmental Protection Agency rates the pickup at 17 mpg, so 15,000 miles requires 882 gallons. At $2.50 per gallon, that’s a total of $2,206 annually and $11,025 for five years. The hybrid’s EPA rating is 45 mpg, using only 333 gallons for 15,000 miles, costing $834 a year and $4,170 for five years. Comparing these two, the fuel savings for the hybrid car is $6,860 for the five-year period. With city ratings of 13 mpg for the pickup and 40 mpg for the Civic, the savings triple. Plus there is a tax incentive of $525 to $2,100 W for the hybrid, so the payback for the Civic’s higher purchase price would happen in the first year. Also, the resale value of the Civic will be much higher than that for the truck at the end of the five years. This simple example of lifecycle cost illustrates why truck and SUV plants are closing. We can take this example into the commercial and industrial sector. The U.S. Dept. of Energy says that electric motor-driven systems consume two-thirds of all electricity consumed by industry. By practicing better management and using the best practices available today, electric consumption can be reduced by nearly one third. Premium motors The Energy Policy Act of 1992 (EPAct) requires that general-purpose motors sold after October 1997 meet certain minimum efficiency requirements defined by National Electrical Manufacturers Assn. (NEMA) MG 1 Table 12-11. Motors with higher efficiencies are called NEMA Premium efficient motors. NEMA defines NEMA Premium motors in its MG 1 standard in tables 12-12 and 12-13. They are available in 1 to 500 hp for voltages of 600 V and less, and 250 to 500 hp for 2,300/4,000 V; speeds are 3,600, 1,800, and 1,200 rpm. There is no industry standard for fractional horsepower NEMA Premium motors with higher than standard efficiencies are available for fractional and two-digit frame sizes. The purchase price of an electric motor is only about 2% of its cost, so a motor with higher efficiency will pay back its higher first cost. Electric motors have an average life of 28 years. Figure 1 illustrates a typical lifecycle cost for an industrial motor. When upgrading to NEMA Premium motors, you may take the opportunity to add features Energy 97.3% Initial purchase 2.0% One rewind 0.7% Figure 1 Typical lifecycle cost for an industrial motor. Source: Baldor Electric Co. Consulting-Specifying Engineer • DECEMBER 2008 57

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - December 2008

Consulting-Specifying Engineer - December 2008 Contents Viewpoint News M/E Roundtable ARC Awards New Construction Gold New Construction Silver New Construction Bronze Renovation Gold Renovation Silver A Green Approach to Air Conditioning Systems Turning Down the Lights Case Study New Products Equipment Lifecycles Advertiser Index Green Space Gas Technology Pure Power Supplement

Consulting-Specifying Engineer - December 2008

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