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Federal Register / Vol. 86, No. 1 / Monday, January 4, 2021 / Rules and Regulations
breakdown torque as specified in NEMA
MG 12016 Table 105 for single-phase motors or 140 percent of the breakdown torque values specified in NEMA MG 1
2016 Table 105 for polyphase motors.
For purposes of this definition, NEMA
MG 12016 Table 105 can be applied to all small electric motors, regardless of whether elements of NEMA MG 12016
Table 105 are identified as for small or medium motors.
DOE also is defining breakdown torque. Consistent with the proposed definition, DOE is defining breakdown torque, in part, as the maximum torque that the motor will develop with rated voltage and frequency applied without an abrupt drop in speed. As previously noted, the phrase abrupt drop in speed references the intrinsic behavior of motors, in which a motor will slow down or stall if the load applied to the motor exceeds the breakdown torque, and indicates that minor reductions in speed observed due to measurement sensitivities are not considered. To provide additional specification for determining breakdown torque based on the physical attributes of a small electric motor, DOE
is also including in the definition that the breakdown torque of a motor is the local maximum of the torque-speed plot of the motor, closest to the synchronous speed of the motor.23
Both the April 2019 NOPR and NEMAs comments explained that on a torque-speed plot, the breakdown torque is the local maximum torque in the region of the plot characterized through reference to the rated torque. The relevant region of the plot can also be characterized through reference to the synchronous speed. The local maximum of the torque-speed plot in the region characterized by the rated torque is the same value as the local maximum of the torque-speed plot in the region characterized by the synchronous speed.
DOE is providing additional detail to define breakdown torque using the synchronous speed, as it is a physical attribute of the motor rather than rated torque, which is a manufacturer declared value.
For the reasons discussed in the preceding paragraphs, DOE is defining breakdown torque as the maximum torque that the motor will develop with rated voltage and frequency applied without an abrupt drop in speed. The breakdown torque is the local maximum of the torque-speed plot of the motor, closest to the synchronous speed of the 23 The synchronous speed of a motor is calculated as follows: 120 f p where f is the frequency at which the motor is operating and p is the number of poles of the motor.

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motor, determined in accordance with NEMA MG 12016.
D. Rated Values Specified for Testing Small Electric Motors DOE notes that the definition of average full-load efficiency at 10 CFR
431.442 specifies that it is determined when the motor operates at the rated frequency, rated load, and rated voltage.
Additionally, industry standards refer to these rated values, which are expected to be known or provided e.g., on the nameplate. However, rated frequency, rated load, and rated voltage are not defined. To provide additional specificity regarding these terms, in the April 2019 NOPR, DOE
proposed to define them to further ensure the comparability of results between motors, and to better ensure reproducible testing for all equipment.
84 FR 17004, 1701717018. In this final rule, DOE is amending 10 CFR 431.442
to establish definitions for rated frequency, rated load, and rated voltage, as discussed in the following sections.
1. Rated Frequency The test procedures and energy conservation standards established under EPCA apply to those regulated motors that are distributed in commerce within the United States. Within the United States, electricity is supplied at 60 hertz Hz; in other regions of the world, electricity is supplied at 50 Hz.
Small electric motors could be designed to operate at frequencies in addition to 60 Hz e.g., motors designed to operate at either 60 or 50 Hz. Therefore, it could be unclear at which frequency the test should be performed. DOE proposed to amend the small electric motor test procedure at 10 CFR 431.442 by defining the term rated frequency as 60 hertz. See 84 FR 17004, 17017.
NEMA commented that explicitly stating that rated frequency is 60 Hz would be beneficial in the case of a motor marked as 60/50 hertz. NEMA, No. 84 at p. 4 The CA IOUs supported DOEs proposal that all tests be performed using a rated frequency of 60
Hz. CA IOUs, No. 86 at p. 3 The Efficiency Advocates supported DOEs proposal to specify that all small electric motor tests be performed using a rated frequency of 60 Hz to remove ambiguity in the test procedure and to ensure that the test procedure reflects the operating frequency in the U.S. Efficiency Advocates, No. 87 at p. 2 DOE did not receive any comments opposing the proposed definition.
DOE notes that 60 Hz as the tested input frequency matches the frequency experienced by the motor when
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installed in the field. In addition, commenters also recommended DOE
require testing at a rated frequency of 60
Hz, as noted. Therefore, in this final rule, DOE is amending 10 CFR 431.442
to establish a definition of rated frequency as 60 hertz.
2. Rated Load Rated load 24 is a term used in industry standards to specify a loading point for motor testing e.g., sections 5.6
and 6.1 in IEEE 1122004, and section 8.2.1 in IEEE 1142010. Typically, a rated load represents a power output expected from the motor e.g., a horsepower value on the nameplate.
The rated load will have a corresponding rated speed and rated torque. In the April 2019 NOPR, DOE
proposed to amend 10 CFR 431.442 by defining rated load as the rated output power of a small electric motor see section III.C for definition of rated output power. 84 FR 17004, 17017.
DOE also proposed that the rated output power given on the motor nameplate be used for any reference to rated load, full rated load, rated full-load, or fullload in an industry standard used for testing small electric motors. Id The Efficiency Advocates supported DOEs proposed definition for rated load, commenting that this specification will help ensure that test procedures are applied consistently. Efficiency Advocates, No. 87 at p. 2 The CA IOUs supported the definition for rated load for small electric motors based on NEMA MG 12016. CA IOUs, No. 86 at p. 3 NEMA commented that qualifying that the rated output power stamped on the name plate of a small motor is equivalent to rated load, full rated load, rated full load or full-load in an industry standard is beneficial and eliminates questions regarding interpretation. NEMA, No. 84 at p. 4
Providing a definition for rated load further ensures the comparability of results between motors, and better ensures reproducible testing. In addition, qualifying that the rated output power is equivalent to rated load, rated full-load, full rated load, or full-load in an industry standard used for testing small electric motors removes any confusion on the interpretation of terms. Commenters also supported clarifying the term rated load.
Accordingly, consistent with its proposal, DOE is amending 10 CFR
431.442 to establish a definition of rated load as the rated output power of a small electric motor.
24 Also referred to as rated full-load, full rated load, or full-load interchangeably.

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