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Table 4 — Electrical Data, Standard Motors
See Legend and Notes below.
Table 5 — Electrical Data, Alternate Motors
See Legend and Notes below.
Legend and Notes For Tables 4 and 5
UNIT V-PH-Hz
†
VOLTAGE
LIMITS
FAN MOTOR POWER SUPPLY
Hp (kW) FLA
Minimum
Circuit Amps
MOCP
40RUA*25
40RUS*25
208/230-3-60 187-253 5.0 (3.73) 14.6/12.8 18.3/16.0 30/25
460-3-60 414-506 5.0 (3.73) 6.4 8.0 15
575-3-60 518-632 5.0 (3.73) 5.1 6.4 15
40RUA*28
40RUS*28
208/230-3-60 187-253 7.5 (5.59) 21.4/19.4 26.9/24.3 45/40
460-3-60 414-506 7.5 (5.59) 9.7 12.1 20
575-3-60 518-632 7.5 (5.59) 7.8 9.8 15
40RUA*30
40RUS*30
208/230-3-60 187-253 10.0 (7.46) 28.2/26.8 35.3/33.5 60/60
460-3-60 414-506 10.0 (7.46) 13.4 16.8 30
575-3-60 518-632 10.0 (7.46) 10.3 12.9 20
UNIT V-PH-Hz
†
VOLTAGE
LIMITS
FAN MOTOR POWER SUPPLY
Hp (kW) FLA
Minimum
Circuit Amps
MOCP
40RUA*25
40RUS*25
208/230-3-60 187-253 7.5 (5.59) 21.4/19.4 26.9/24.3 45/40
460-3-60 414-506 7.5 (5.59) 9.7 12.1 20
575-3-60 518-632 7.5 (5.59) 7.8 9.8 15
40RUA*28
40RUA*30
40RUS*28
40RUS*30
208/230-3-60 187-253 10.0 (7.46) 28.2/26.8 35.3/33.5 60/60
460-3-60 414-506 10.0 (7.46) 13.4 16.8 30
575-3-60 518-632 10.0 (7.46) 10.3 12.9 20
LEGEND
†
Motors are designed for satisfactory operation within 10% of nominal
voltages shown. Voltages should not exceed the limits shown in the
Voltage Limits column.
NOTES:
1. Minimum circuit amps (MCA) and MOCP values are calculated in accor-
dance with NEC (National Electrical Code), Article 440.
2. Motor FLA values are established in accordance with UL (Underwriters’
Laboratories) Standard 1995.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply voltage is
greater than 2%. Use the following formula to determine the percentage of
voltage imbalance.
EXAMPLE: Supply voltage is 400-3-50.
AB = 393 v
BC = 403 v
AC = 396 v
Determine maximum deviation from average voltage
(AB) 397 – 393 = 4 v
(BC) 403 – 397 = 6 v
(AC) 397 – 396 = 1 v
Maximum deviation is 6 v.
Determine percent voltage imbalance.
This amount of phase imbalance is satisfactory because it is below the maxi-
mum allowable 2%.
FLA — Full Load Amps
MOCP
—
Maximum Overcurrent Protection
% Voltage Imbalance = 100 x
max voltage deviation from average voltage
average voltage
Average Voltage =
393 + 403 + 396
3
=
1192
3
=
397
% Voltage Imbalance = 100 x
6
397
=1.5%
IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.