§ 431.24 - Determination of efficiency.

When a party determines the energy efficiency of an electric motor in order to comply with an obligation imposed on it by or pursuant to Part C of Title III of EPCA, 42 U.S.C. 6311-6316, this section applies. This section does not apply to enforcement testing conducted pursuant to § 431.127.

(a) Provisions applicable to all electric motors. (1) General Requirements. The average full load efficiency of each basic model of electric motor must be determined either by testing in accordance with § 431.23 of this subpart, or by application of an alternative efficiency determination method (AEDM) that meets the requirements of paragraphs (a)(2) and (3) of this section, provided, however, that an AEDM may be used to determine the average full load efficiency of one or more of a manufacturer's basic models only if the average full load efficiency of at least five of its other basic models is determined through testing.

(2) Alternative efficiency determination method. An AEDM applied to a basic model must be:

(i) Derived from a mathematical model that represents the mechanical and electrical characteristics of that basic model, and

(ii) Based on engineering or statistical analysis, computer simulation or modeling, or other analytic evaluation of performance data.

(3) Substantiation of an alternative efficiency determination method. Before an AEDM is used, its accuracy and reliability must be substantiated as follows:

(i) The AEDM must be applied to at least five basic models that have been tested in accordance with § 431.23 of this subpart, and

(ii) The predicted total power loss for each such basic model, calculated by applying the AEDM, must be within plus or minus ten percent of the mean total power loss determined from the testing of that basic model.

(4) Subsequent verification of an AEDM. (i) Each manufacturer shall periodically select basic models representative of those to which it has applied an AEDM, and for each basic model selected shall either:

(A) Subject a sample of units to testing in accordance with §§ 431.23 and 431.24(b)(2) by an accredited laboratory that meets the requirements of § 431.25,

(B) Have a certification body recognized under § 431.27 certify its nominal full load efficiency, or

(C) Have an independent state-registered professional engineer, who is qualified to perform an evaluation of electric motor efficiency in a highly competent manner and who is not an employee of the manufacturer, review the manufacturer's representations and certify that the results of the AEDM accurately represent the total power loss and nominal full load efficiency of the basic model.

(ii) Each manufacturer that has used an AEDM under this section shall have available for inspection by the Department of Energy records showing: the method or methods used; the mathematical model, the engineering or statistical analysis, computer simulation or modeling, and other analytic evaluation of performance data on which the AEDM is based; complete test data, product information, and related information that the manufacturer has generated or acquired pursuant to §§ 431.24(a)(3) and (a)(4)(i); and the calculations used to determine the average full load efficiency and total power losses of each basic model to which the AEDM was applied.

(iii) If requested by the Department, the manufacturer shall conduct simulations to predict the performance of particular basic models of electric motors specified by the Department, analyses of previous simulations conducted by the manufacturer, sample testing of basic models selected by the Department, or a combination of the foregoing.

(5) Use of a certification program or accredited laboratory. (i) A manufacturer may have a certification program, that DOE has classified as nationally recognized under § 431.27, certify the nominal full load efficiency of a basic model of electric motor, and issue a certificate of conformity for the motor.

(ii) For each basic model for which a certification program is not used as described in paragraph (a)(5)(i) of this section, any testing of the motor pursuant to § 431.24(a)(1) through (3) to determine its energy efficiency must be carried out in accordance with § 431.24(b), in an accredited laboratory that meets the requirements of § 431.25. (This includes testing of the basic model, pursuant to § 431.24(a)(3)(i), to substantiate an AEDM.)

(b) Additional testing requirements applicable when a certification program is not used. (1) Selection of basic models for testing. (i) Basic models must be selected for testing in accordance with the following criteria:

(A) Two of the basic models must be among the five basic models with the highest unit volumes of production by the manufacturer in the prior year, or during the prior 12 calendar month period beginning in 1997, 1 whichever is later;

(B) The basic models should be of different horsepowers without duplication;

(C) The basic models should be of different frame number series without duplication; and

(D) Each basic model should be expected to have the lowest nominal full load efficiency among the basic models with the same rating (“rating” as used here has the same meaning as it has in the definition of “basic model”).

(ii) In any instance where it is impossible for a manufacturer to select basic models for testing in accordance with all of these criteria, the criteria shall be given priority in the order in which they are listed. Within the limits imposed by the criteria, basic models shall be selected randomly.

(2) ection of units for testing. For each basic model selected for testing,2 a sample of units shall be selected at random and tested. The sample shall be comprised of production units of the basic model, or units that are representative of such production units. The sample size shall be not fewer than five units, except that when fewer than five units of a basic model would be produced over a reasonable period of time (approximately 180 days), then each unit shall be tested. In a test of compliance with a represented average or nominal efficiency:

(i) The average full-load efficiency of the sample X which is defined by

ER05OC99.003 where Xi is the measured full-load efficiency of unit i and n is the number of units tested, shall satisfy the condition: ER05OC99.004 where RE is the represented nominal full-load efficiency, and

(ii) The lowest full-load efficiency in the sample Xmin, which is defined by

ER05OC99.005 shall satisfy the condition ER05OC99.006

(3) Substantiation of an alternative efficiency determination method. The basic models tested under § 431.24(a)(3)(i) must be selected for testing in accordance with paragraph (b)(1), and units of each such basic model must be tested in accordance with paragraph (b)(2) by an accredited laboratory that meets the requirements of § 431.25.