Johnson Controls VFD66 Series Product/Technical Bulletin page 9

Amperes
10.6
VFD66Exx Type
10.0
VFD66Cxx Type
7.5
5.0
VFD66Axx Type
4.0
2.5
0
o
122 F 126 F
o o
50 C 52 C
Figure 12: 208/230 VAC Temperature De-Rating
Amperes
6.0
VFD66Fxx Type
5.5
4.5
VFD66Dxx Type
3.6
3.0
2.2
VFD66Bxx Type
1.8
1.5
0
o
122 F
126 F
o
50 C
52 C
Figure 13: 400/460 VAC Temperature De-Rating
Altitude De-Rating
See Table 7 for altitude multipliers. Use the following
formula to determine the adjusted rating:
Temperature
De-Rated
Maximum
X
Output
Amperes
o o
131 F o 136 F
o
55 C o 58 C
Temperature
o
136 F
o
o
131 F
58 C o
o
55 C o
Temperature
De-Rated
Altitude Maximum
Multiplier =
Output
Amperes
VFD66 Series Condenser Fan Speed Controls Product/Technical Bulletin
Table 7: Altitude Multipliers for De-Rating
Altitude Range
0-3300 ft (0-1000 m)
3300-4300 ft (1000-1305 m)
4300-5300 ft (1305-1610 m)
5300-6300 ft (1610-1915 m)
6300-7300 ft (1915-2220 m)
7300-8300 ft (2220-2525 m)
8300-9300 ft (2525-2830 m)
9300-10300 ft (2830-3135 m)
10300-11300 ft (3135-3440 m)
o
140 F
o
60 C
De-Rating Examples
For these examples, the control used is a VFD66Exx
type. See Figure 12, Figure 13, and Table 7.
•
If a VFD66Exx type (208/230 VAC) is used and
the temperature is below 122°F (50°C), the VFD66
control may be used for loads up to 10.6 amperes
at any altitude below 3300 ft (1000 m).
•
If the temperature around the VFD66 control
reaches 140°F (60°C), the rating is different.
According to Figure 12, the VFD66 control is rated
for only 7.5 amperes at 140°F (60°C).
•
If the VFD66 control is used in Denver, Colorado
(altitude 5200 ft), the output rating is reduced.
(See Table 7.) When the temperature is less than
122°F (50°C), the VFD66 control is rated for
o
140 F
9.96 amperes, as shown by the equation:
o
60 C
De-Rated Maximum Output Amperes = 10.6 Amperes
x 0.94 = 9.96 Amperes
•
If the VFD66 control is used in Denver, Colorado
(altitude 5200 ft), and the ambient temperature
reaches 140°F (60°C), then the VFD66 control is
de-rated to a 7.5-ampere maximum current draw
due to the high ambient temperature and is further
de-rated to 7.05 amperes of current draw because
of high altitude.
De-rated Maximum Output Amperes = 7.5 Amperes x
0.94 = 7.05 Amperes
Altitude Multiplier
1.0
0.97
0.94
0.91
0.88
0.86
0.83
0.80
0.78
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