UFC 3 -520-01
June 10, 2002
Table 7-1. Minimum Full -Load Motor Efficiencies
Open Motors
Enclosed Motors
Watts
1,200 RPM 1,800 RPM 3,600 RPM 1,200 RPM 1,800 RPM 3,600 RPM
1
746
80.0
82.5
--
80.0
82.5
75.5
1.5
1,119
84.0
84.0
82.5
85.5
84.0
82.5
2
1,492
85.5
84.0
84.0
86.5
84.0
84.0
3
2,238
86.5
86.5
84.0
87.5
87.5
85.5
5
3,730
87.5
87.5
85.5
87.5
87.5
87.5
7.5
5,595
88.5
88.5
87.5
89.5
89.5
88.5
10
7,460
90.2
89.5
88.5
89.5
89.5
89.5
15
11,190
90.2
91.0
89.5
90.2
91.0
90.2
20
14,920
91.0
91.0
90.2
90.2
91.0
90.2
25
18,650
91.7
91.7
91.0
91.7
92.4
91.0
30
22,380
92.4
92.4
91.0
91.7
92.4
91.0
40
29,840
93.0
93.0
91.7
93.0
93.0
91.7
50
37,300
93.0
93.0
92.4
93.0
93.0
92.4
60
44,760
93.6
93.6
93.0
93.6
93.6
93.0
75
55,950
93.6
94.1
93.0
93.6
94.1
93.0
100
74,600
94.1
94.1
93.0
94.1
94.5
93.6
125
93,250
94.1
94.5
93.6
94.1
94.5
94.5
150
111,900
94.5
95.0
93.6
95.0
95.0
94.5
200
149,200
94.5
95.0
94.5
95.0
95.0
95.0
250
186,500
95.4
95.4
94.5
95.0
95.0
95.4
300
223,800
95.4
95.4
95.0
95.0
95.4
95.4
350
261,100
95.4
95.4
95.0
95.0
95.4
95.4
400
298,400
--
95.4
95.4
--
95.4
95.4
450
335,700
--
95.8
95.8
--
95.4
95.4
500
373,000
--
95.8
95.8
--
95.8
95.4
7-1.5
Select motors according to expected service conditions. Usual service
conditions, as defined in NEMA MG 1, Motors and Generators, include:
Exposure to an ambient temperature between 0 C (32 F) and 40 C (104 F).
Installation in areas or enclosures that do not seriously interfere with the ventilation
of the machine.
Operation within a tolerance of 10 percent of rated voltage.
Altitude not above 1,006 meters (3,300 feet). Table 7 -2 provides the typical motor
derating for operation above this altitude.
Operation within a tolerance of 5 percent of rated frequency.
Operation with a voltage unbalance of 1 percent or less.
7-2
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