Jumpers on J7 and J8 must be set for the correct input
voltage range and number of input devices. (See
Table 4.) Jumper block J7 sets the voltage range for
the input signal(s). If the jumper on jumper block J7 is
incorrectly set, the control may operate in an
unexpected manner. See
Jumper block J8 selects the number of input signals
used. When dual inputs are selected, Terminal 3 of
TB3 (TB3-3) is enabled. The VFD66 control varies the
speed of the fan motor in accordance with the higher
value of the two input signals received. If the jumper
on jumper block J8 is incorrectly set, the control may
operate in an unexpected manner. See
Jumper block J9 selects maximum frequency output of
the control. Remove the jumper for 50 Hz motors,
typically used in Europe. Install the jumper for 60 Hz
motors, typically used in North America. Power to the
VFD66 control must be disconnected and reconnected
before frequency changes take effect.
De-Rating the VFD66 Control for
High Temperatures and High Altitudes
Ambient air temperature and altitude of the installation
affect the maximum output ampere rating of the
VFD66 control. High air temperature makes the heat
sink less effective in dissipating the generated heat.
High altitudes have thinner air than lower altitudes,
which is less effective in dissipating heat. The less
effective the heat sink is, the lower the maximum
output ampere rating of the VFD66 control.
Temperature De-Rating
For temperatures up to 122
°
F (50
°
C), the maximum
output ampere rating is unaffected by temperature. At
temperatures between 122
°
F (50
°
C) and 140
°
F
(60
°
C), the maximum output ampere rating is
decreased. The VFD66 controls are not designed to
operate in temperatures above 140
°
F (60
°
C).
See Figure 10 for temperature de-rating for
208/230 VAC models. See Figure 11 for temperature
de-rating for 400/460 VAC models.
Amperes
Temperature
10.0
0
5.0
7.5
2.5
122 F
50 C
o
o
140 F
60 C
o
o
131 F
55 C
o
o
126 F
52 C
o
o
136 F
58 C
o
o
4.0
10.6
VFD66Axx Type
VFD66Cxx Type
VFD66Exx Type
Figure 10: 208/230 VAC Temperature De-Rating
Amperes
Temperature
6.0
0
3.0
4.5
1.5
122 F
50 C
o
o
140 F
60 C
o
o
5.5
1.8
3.6
2.2
131 F
55 C
o
o
126 F
52 C
o
o
136 F
58 C
o
o
VFD66Fxx Type
VFD66Dxx Type
VFD66Bxx Type
Figure 11: 400/460 VAC Temperature De-Rating
Altitude De-Rating
See Table 5 for altitude multipliers. Use the following
formula to determine the adjusted rating:
Temperature
De-Rated
Maximum
Output
Amperes
X
Altitude
Multiplier =
De-Rated
Maximum
Output
Amperes
VFD66 Series Condenser Fan Speed Controls Product/Technical Bulletin
7
