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SmartFan Wisp
II is designed to control small DC fans. The low voltage
version includes a temperature alarm for increased safety.
The high voltage version accepts a 38 to 75 VDC supply voltage
range and includes a voltage limiter set to 50 VDC.
Wisp II includes
both a temperature sensor and control circuit packaged in
a probe for convenient remote or on-fan mounting. The controller
uses a linear operating principle, applying a smooth DC voltage
to the fans. It is available for both Closed-Loop (temperature
regulating) and Open-Loop (temperature compensating) applications.
The Wisp II controller’s
power rating is sufficient to control up to three typical
120 mm fans. The low voltage version can be used with 12 or
24 VDC fans. The high voltage version is used with 48 VDC
fans.
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Features
- Noise reduction
typically 15 dB(A) at idle speed
- Completely self
contained including sensor
- Controls 12,
24 and 48 VDC fans
- Low voltage
version (018W1XXX) accepts a supply voltage range of 11.5
to 30 VDC and includes a temperature alarm output that can
drive logic or a red LED
- High voltage
version (048W0XXX) accepts a supply voltage range of 38
to 75 VDC and includes a voltage limiter set to 50 VDC
- 70ºC maximum
operating temperature
- Supplied with
15 inch (24 AWG) wires and mounting clamp.
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| SPECIFICATIONS |
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Part
Number
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Type
(1)
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Supply
Voltage Range
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Maximum Watts to Fans (2)
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Control
Temperature
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Full
Speed / Idle Speed Temperatures
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Closed-Loop
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11.5
– 30 VDC
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20
Watts
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N/A
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Closed-Loop
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38
– 75 VDC
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20
(3)
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N/A
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018W135P
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Open-Loop
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11.5
– 30 VDC
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20
Watts
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N/A
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35°C
/ 23°C
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048W035P
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Open-Loop
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38
– 75 VDC
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20
(3)
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N/A
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35°C
/ 23°C
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| (1)
Closed-Loop types are installed near equipment exhaust, Open-Loop
types at equipment inlet. |
| (2)
Air temperature of 70°C or less, air velocity of 200 ft/min
or greater. |
| (3)
Above 50 VDC supply, power is linearly derated, reaching 10
Watts at 75 VDC. |
| U.S.
Patents 4,659,290, 4,722,699 and 5,364,026 |
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| INSTALLATION |
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Mounting
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| Mount
Wisp II in a moving air stream using the cable clamp supplied.
Avoid placing the sensor (located at the tip) near a hot component
as this may result in heating by radiation. To minimize heating
of the sensor by the Wisp II circuits, avoid mounting the unit
vertically with the sensor at the top. |
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| Location
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| Install
a closed-loop unit at or near the equipment exhaust where it
can sense any upstream event that could affect cabinet temperature.
Install an open-loop (P suffix) unit at or near the equipment
inlet. |
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| Connections
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Figure
1 Connection
diagram for P/N 018W0XX with LED temperature alarm indication.
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Figure
2 Connection
diagram for P/N 018W0XX with logic circuit temperature
alarm indication.
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| Temperature
Alarm Output |
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For Part Nos. 018W1XXX,
a temperature alarm signal is available through the yellow
and black wires. An alarm can be indicated using an external
LED (Figure 1) or logic circuit (Figure 2).
| Alarm
Type: |
Non-Isolated
Open-Collector |
| Trigger: |
10°C
Above Control Temperature |
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| Alarm
States: |
Conducting
(Closed), Above Trigger |
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Cut-Off
(Open), Below Trigger |
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| Max.
Voltage: |
30
VDC |
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| Max.
Current: |
4
mA DC at 0.4 VDC (Logic Circuit), |
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10
mA DC (LED Circuit) |
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Figure
3 Connection
diagram for P/N 048W0XX and P/N 018W1XX when the temperature
alarm output is not used.
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| OPERATION |
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Fan Speed vs.
Sensor Temperature
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| The
relationship between fan speed, as a percentage of full speed,
and sensed temperature is shown in Figure 4. Full speed occurs
at the Control Temperature (Tc ). Minimum speed temperature
(approx. 50% of full speed) depends on part number. For closed
loop units, the “X” in Figure 4 is equal to 4. For open loop
units the “X” in Figure 4 is equal to 12. |
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| Figure
4 Fan
Speed vs. sensor temperature |
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| Voltage
Regulator and Limiter |
| Part
Nos. 048W0XXX are intended to cover telecommunications applications
using supply voltages ranging from 38 to 75 VDC. Wisp II regulates
minimum (idle) voltage at 26 VDC. Maximum voltage applied to
the fans is limited to 50 VDC. For supply voltages above 50
VDC, power is linearly derated based on the curve shown in Figure
5. |
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Figure
5
Power derating curve
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