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CONFIRM FAN/MOTOR COMPATIBILITY
Confirm TRIAC (voltage control) compatibility with
the fan/motor manufacturer before installation.
Attempting to control a motor that is not compatible
could cause excessive heating and permanent
damage.
CONTROL MODES
The AC-VX has two modes of operation:
Fan Speed Proportional to Analog Control Signal: When used in this mode of operation, the AC-VX
controls fan speed in proportion to a 0-20 mADC, 0-5
VDC, or 0-10 VDC analog control signal. Idle speed
ON/OFF and the idle speed voltage can be adjusted in
this mode (see jumper settings).
Fan Speed Proportional to Temperature Sensor
Input: When used in this mode of operation, the AC-VX
controls fan speed in proportion to temperature as
sensed by a thermistor (CRI P/N P10-F). The following
parameters can be adjusted using the four jumpers
located on the AC-VX: Idle speed, Idle speed ON/OFF,
full speed temperature, and differential temperature (see
jumper settings).
JUMPER SETTINGS
Diff °F (J1): Use this jumper to set the temperature
difference between full speed and idle speed. The
setting is only applicable to applications using the
temperature sensor input (SENSE). The three
temperature differential settings are 5, 10, and 15°F.
The factory setting is 10°F.
Idle Speed (J2): Use this jumper to set the idle voltage
point, when the idle speed (J3) is set to ON. With the
idle speed set to OFF, this jumper sets the point at which
the voltage applied to the fan shuts off. The three
positions in order of increasing idle voltage are LOW,
MID, and HIGH. The factory setting is MID.
ON/OFF (J3): Use this jumper to determine if the fan
voltage should shut off below the idle speed set by
header J2. The factory setting is ON.
Full Speed °F (J4): Use this jumper to set the
temperature above which the maximum voltage is
applied to the fan. The setting is only applicable to
applications using the temperature sensor input
(SENSE). The four temperature settings are 75, 80, 85,
and 90°F. The factory setting is 80°F.
Powering the Fans ON/OFF: When the fan idle is set
to OFF using jumper J3, the fan voltage drops to zero
when the control signal commands the output to go
below the idle speed set-point. The fan voltage will
come on slightly above (5%) the idle speed OFF point.
This is a built in hysteresis feature. Example: If header
J3 is set to OFF and header J2 is set to MID, the fan
voltage will drop to zero below a 35% control signal and
come back on when a control signal above 42% is
applied.
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Power Factor Adjustment: The power factor of the
connected fan load is sensed at power up. This
information is used by the microcontroller to adjust for
optimum fan speed range. As a result, two fan types will
have different voltage vs. control input profiles if their
power factors are significantly different. For instance,
the voltage range available for a high power factor fan
will be larger than a low power factor fan.
Low Line Voltage Shut-Off: If the line voltage drops
below a predetermined level, the output power is halted
until the condition is corrected. The feature functions as
follows: (1) The line voltage is sensed at power up. (2)
This line voltage value is used to select either a 95 VAC
or a 190 VAC low voltage shut-off. For instance, if a
nominal 115 VAC line voltage is sensed at power up, the
95 VAC cut-off is selected. In this instance, the output
power will be halted for line voltages below 95 VAC.
Fixed Start-Up Delay: There is a fixed period of
approximately 3 to 5 seconds before the control voltage
is applied to the fan load. This brief delay occurs
whenever the line power applied to the AC-VX is
switched from OFF to ON. During this time fan voltage
is at 0 VAC. This brief delay, which is not adjustable by
the user, is required by the microprocessor to initialize
system parameters.
Performance Graphs: The following graphs summarize
the AC-VX performance with a typical Permanently Split
Capacitor (PSC) type fan at 115 VAC line voltage.
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