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Fan Connections
For three wire DC fans operating at supply voltages
between 6.0 and 60.0 VDC, TachScan-3 distributes power
to the fans in addition to accepting tachometer pulses from
the fans. Connect the fan wires to J1, J2 and J3 using the
suggested hardware, or equivalent. For applications using
less than three fans, any of the three connectors (J1, J2,
J3) can be used to monitor tachometer signals. The fan
wires are usually color coded with red for +, black for - and
white or yellow for A (alarm). Input current must not
exceed 4.0 Amps. When TachScan-3 is used with a
SmartFan speed controller, the power output of the speed
controller is connected to J7.
AC Fan Alarm Monitoring
Order these part numbers when using TachScan-3 with
AC fans.
P/N 030M3205-F for 1 mA Alarm Sinking Current
P/N 030M320R4-F for 100 mA Alarm Sinking Current
TachScan-3 cannot distribute AC power to AC fans. AC
fans usually have 5 wires, 2 for power and 3 for the
tachometer pulse circuit. Connect the AC fan power leads
to the rated source of power. Connect the tachometer
pulse leads (+, -, tach pulse) to J1, J2, and J3. TachScan-
3 distributes power to run the tachometer pulse circuits
within the fans. Apply a DC voltage as specified by the fan
manufacturer for the tachometer pulse circuits at J7.
Use with a SmartFan Speed Controller
Because of the wide range of power supply voltages that
may be connected to J7, TachScan-3 may be used with
any DC SmartFan speed controller. The power output of
the speed controller that would otherwise be connected
directly to the fan load is instead connected to J7.
TachScan-3 in turn distributes this power to the fans. |
Figure 1: Typical wiring diagram
J1 - Fan Power and Tach Input
J2 - Fan Power and Tach Input
J3 - Fan Power and Tach Input
J4 - Alarm channels Setting
J5 - Trigger Speed Setting
J6 - Alarm Outputs
J7 - Supply Power |
P/Ns 030M320-F and 030M3205-F
R2 >= V2/1, kOhms
R1 >= V1/1, kOhms
P/Ns 030M320R-F and 030M320R4-F
R2 >= V2/100, kOhms
R1 >= V1/100, kOhms
Above Trigger Speed
Sense_VA = V1 VDC
Sense_VB = <0.4 VDC
Below Trigger Speed
Sense_VA = <0.4 VDC
Sense_VB = V2 VDC |
| Figure 2: Multi-board configuration for variable fan speed control and tachometer alarm monitoring. |
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