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PDFWAC 51-11C-40508

Section C405.8—Electric motors.

C405.8 Electric motor efficiency. All electric motors, fractional or otherwise, shall meet the minimum efficiency requirements of Tables C405.8(1) through C405.8(4) when tested and rated in accordance with DOE 10 C.F.R. 431. The efficiency shall be verified through certification under an approved certification program or, where no certification program exists, the equipment efficiency ratings shall be supported by data furnished by the motor manufacturer.
EXCEPTION:
The standards in this section shall not apply to the following exempt electric motors.
 
1. Air-over electric motors.
 
2. Components sets of an electric motor.
 
3. Liquid-cooled electric motors.
 
4. Submersible electric motors.
 
5. Inverter-only electric motors.
Fractional hp fan motors that are 1/12 hp or greater and less than 1 hp (based on output power) which are not covered by Tables C405.8(3) and C405.8(4) shall be electronically commutated motors or shall have a minimum motor efficiency of 70 percent when rated in accordance with DOE 10 C.F.R. 431. These motors shall also have the means to adjust motor speed for either balancing or remote control. Belt-driven fans may use sheave adjustments for airflow balancing in lieu of a varying motor speed.
EXCEPTIONS:
1. Motors that are an integral part of specialized process equipment.
 
2. Where the motor is integral to a listed piece of equipment for which no complying motor has been approved.
 
3. Motors used as a component of the equipment meeting the minimum efficiency requirements of Section C403.3.2 and Tables C403.3.2(1) through C403.3.2(16) provided that the motor input is included when determining the equipment efficiency.
 
4. Motors in the airstream within fan-coils and terminal units that operate only when providing heating to the space served.
 
5. Fan motors that are not covered by Tables C405.8(1) through C405.8(4) and are used to power heat recovery ventilators, energy recovery ventilators, or local exhaust fans in Group R subject to the efficacy requirements of Section C403.8.4.
 
6. Domestic clothes dryer booster fans, range hood exhaust fans, and domestic range booster fans that operate intermittently.
 
7. Radon and contaminated soil exhaust fans.
 
8. Group R heat recovery ventilator and energy recovery ventilator fans that are less than 400 cfm.
Table C405.8(1)
Minimum Nominal Full-load Efficiency for NEMA Design A, NEMA Design B and IEC Design N Motors (Excluding Fire Pump) Electric Motors at 60 Hza,b
Motor horsepower (Standard kilowatt equivalent)
Nominal full-load efficiency (%) as of June 1, 2016
2 pole
4 pole
6 pole
8 pole
Enclosed
Open
Enclosed
Open
Enclosed
Open
Enclosed
Open
1 (0.75)
77.0
77.0
85.5
85.5
82.5
82.5
75.5
75.5
1.5 (1.1)
84.0
84.0
86.5
86.5
87.5
86.5
78.5
77.5
2 (1.5)
85.5
85.5
86.5
86.5
88.5
87.5
84.0
86.5
3 (2.2)
86.5
85.5
89.5
89.5
89.5
88.5
85.5
87.5
5 (3.7)
88.5
86.5
89.5
89.5
89.5
89.5
86.5
88.5
7.5 (5.5)
89.5
88.5
91.7
91.0
91.0
90.2
86.5
89.5
10 (7.5)
90.2
89.5
91.7
91.7
91.0
91.7
89.5
90.2
15 (11)
91.0
90.2
92.4
93.0
91.7
91.7
89.5
90.2
20 (15)
91.0
91.0
93.0
93.0
91.7
92.4
90.2
91.0
25 (18.5)
91.7
91.7
93.6
93.6
93.0
93.0
90.2
91.0
30 (22)
91.7
91.7
93.6
94.1
93.0
93.6
91.7
91.7
40 (30)
92.4
92.4
94.1
94.1
94.1
94.1
91.7
91.7
50 (37)
93.0
93.0
94.5
94.5
94.1
94.1
92.4
92.4
60 (45)
93.6
93.6
95.0
95.0
94.5
94.5
92.4
93.0
75 (55)
93.6
93.6
95.4
95.0
94.5
94.5
93.6
94.1
100 (75)
94.1
93.6
95.4
95.4
95.0
95.0
93.6
94.1
125 (90)
95.0
94.1
95.4
95.4
95.0
95.0
94.1
94.1
150 (110)
95.0
94.1
95.8
95.8
95.8
95.4
94.1
94.1
200 (150)
95.4
95.0
96.2
95.8
95.8
95.4
94.5
94.1
250 (186)
95.8
95.0
96.2
95.8
95.8
95.8
95.0
95.0
300 (224)
95.8
95.4
96.2
95.8
95.8
95.8
 
350 (261)
95.8
95.4
96.2
95.8
95.8
95.8
400 (298)
95.8
95.8
96.2
95.8
 
450 (336)
95.8
96.2
96.2
96.2
500 (373)
95.8
96.2
96.2
96.2
a
Nominal efficiencies shall be established in accordance with DOE 10 C.F.R. 431.
b
For purposes of determining the required minimum nominal full-load efficiency of an electric motor that has a horsepower or kilowatt rating between two horsepower or two kilowatt ratings listed in this table, each such motor shall be deemed to have a listed horsepower or kilowatt rating, determined as follows:
 
1. A horsepower at or above the midpoint between the two consecutive horsepowers shall be rounded up to the higher of the two horsepowers.
 
2. A horsepower below the midpoint between the two consecutive horsepowers shall be rounded down to the lower of the two horsepowers.
 
3. A kilowatt rating shall be directly converted from kilowatts to horsepower using the formula 1 kW = (1/0.746) horsepower. The conversion should be calculated to three significant decimal places, and the resulting horsepower shall be rounded in accordance with 1 or 2, whichever applies.
Table C405.8(2)
Minimum Nominal Full-load Efficiency for NEMA Design C and IEC Design H Motors at 60 Hza,b
Motor horsepower
(Standard kilowatt equivalent)
Nominal full-load efficiency (%) as of June 1, 2016
4 pole
6 pole
8 pole
Enclosed
Open
Enclosed
Open
Enclosed
Open
1 (0.75)
85.5
85.5
82.5
82.5
75.5
75.5
1.5 (1.1)
86.5
86.5
87.5
86.5
78.5
77.5
2 (1.5)
86.5
86.5
88.5
87.5
84.0
86.5
3 (2.2)
89.5
89.5
89.5
88.5
85.5
87.5
5 (3.7)
89.5
89.5
89.5
89.5
86.5
88.5
7.5 (5.5)
91.7
91.0
91.0
90.2
86.5
89.5
10 (7.5)
91.7
91.7
91.0
91.7
89.5
90.2
15 (11)
92.4
93.0
91.7
91.7
89.5
90.2
20 (15)
93.0
93.0
91.7
92.4
90.2
91.0
25 (18.5)
93.6
93.6
93.0
93.0
90.2
91.0
30 (22)
93.6
94.1
93.0
93.6
91.7
91.7
40 (30)
94.1
94.1
94.1
94.1
91.7
91.7
50 (37)
94.5
94.5
94.1
94.1
92.4
92.4
60 (45)
95.0
95.0
94.5
94.5
92.4
93.0
75 (55)
95.4
95.0
94.5
94.5
93.6
94.1
100 (75)
95.4
95.4
95.0
95.0
93.6
94.1
125 (90)
95.4
95.4
95.0
95.0
94.1
94.1
150 (110)
95.8
95.8
95.8
95.4
94.1
94.1
200 (150)
96.2
95.8
95.8
95.4
94.5
94.1
NR - No requirement.
a
Nominal efficiencies shall be established in accordance with DOE 10 C.F.R. 431.
b
For purposes of determining the required minimum nominal full-load efficiency of an electric motor that has a horsepower or kilowatt rating between two horsepower or two kilowatt ratings listed in this table, each such motor shall be deemed to have a listed horsepower or kilowatt rating, determined as follows:
 
1. A horsepower at or above the midpoint between the two consecutive horsepowers shall be rounded up to the higher of the two horsepowers.
 
2. A horsepower below the midpoint between the two consecutive horsepowers shall be rounded down to the lower of the two horsepowers.
 
3. A kilowatt rating shall be directly converted from kilowatts to horsepower using the formula 1 kW = (1/0.746) horsepower. The conversion should be calculated to three significant decimal places, and the resulting horsepower shall be rounded in accordance with 1 or 2, whichever applies.
Table C405.8(3)
Minimum Average Full Load Efficiency for Polyphase Small Electric Motorsa
OPEN MOTORS
NUMBER OF POLES ==˃
2
4
6
SYNCHRONOUS SPEED (RPM) ==˃
3600
1800
1200
MOTOR HORSEPOWER ▼
0.25
65.6
69.5
67.5
0.33
69.5
73.4
71.4
0.50
73.4
78.2
75.3
0.75
76.8
81.1
81.7
1
77.0
83.5
82.5
1.5
84.0
86.5
83.8
2
85.5
86.5
N/A
3
85.5
86.9
N/A
a Average full load efficiencies shall be established in accordance with 10 C.F.R. 431.
Table C405.8(4)
Minimum Average Full Load Efficiency For Capacitor-start Capacitor-run and Capacitor-start Induction-run Small Electric Motorsa
OPEN MOTORS
NUMBER OF POLES ==˃
2
4
6
SYNCHRONOUS SPEED (RPM) ==˃
3600
1800
1200
MOTOR HORSEPOWER ▼
0.25
66.6
68.5
62.2
0.33
70.5
72.4
66.6
0.50
72.4
76.2
76.2
0.75
76.2
81.8
80.2
1
80.4
82.6
81.1
1.5
81.5
83.8
N/A
2
82.9
84.5
N/A
3
84.1
N/A
N/A
a Average full load efficiencies shall be established in accordance with 10 C.F.R. 431.
[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapters 19.27A and 19.27 RCW. WSR 22-14-091, 23-12-101, and 23-20-021, § 51-11C-40508, filed 7/1/22, 6/7/23, and 9/25/23, effective 3/15/24. Statutory Authority: RCW 19.27A.025, 19.27A.045 and chapter 19.27 RCW. WSR 20-21-080, § 51-11C-40508, filed 10/19/20, effective 2/1/21. Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-40508, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-40508, filed 1/19/16, effective 7/1/16. Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-40508, filed 2/1/13, effective 7/1/13.]