DC fan speed controller probe WispII

SmartFan® Wisp II DC Fan Speed Controller- Probe

  • Regulates temperature by varying fan voltage

  •    Controls one or more 12V or 24V fans up to 20W
  •    Control and temperature sensor in one probe
  •    Custom temperature settings for orders as low as 75 units
Operation / Installation PDF

Wisp II Datasheet

SmartFan Wisp II is a fan controller designed to control one or more small DC fan. The Wisp includes a temperature sensor, control circuit, and temp. alarm output conveniently packaged in one small probe for 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. Wisp II accepts an 11.5 to 30 VDC supply voltage range for controlling 12 and 24 VDC fans. Custom wire lengths, control temperatures, and slopes are available.

Specifications Features
  • » Input Voltage: 11.5 to 30VDC
  • » Power Rating: 20 Watts
  • » Size: 3.0″ (76.2mm) L x 0.5″ (12.7mm) ∅
  • » Connections: 15″ (24awg) wires connect power, fans & alarm output
  • » Weight (with clamp): 0.57oz. (16.2g)
  • » Operating Temperature: -20°C to 70° C
  • » Relative Humidity: 95% non-condensing
  • » Storage Temperature: -40°C to 125°C


  • » Controls 12VDC and 24VDC fans
  • » Typical noise reduction at idle speed: 13dB(A)
  • » Available in open-loop and closed-loop models
  • » Over temperature alarm output
  • » Supplied with Aluminum mounting clamp
  • » RoHS compliant
  • » Factory customization for orders as low as 75 units


SmartFan Wisp II DC Fan Speed Controller – Probe Dimensions

SmartFan Wisp II Fan Speed Control Probe

For CAD drawings, use the links in Additional Information below.

SmartFan Wisp II DC Fan Speed Controller Part Numbers

Part Number Type1 Supply Voltage Range Maximum Watts
to Fans2
Control Temperature Full Speed / Idle Speed Temperatures
018W135-F Closed-Loop 11.5 to 30 VDC 20 Watts 35°C N/A
018W140-F 40°C
018W135P-F Open-Loop N/A 35°C / 23°C

1. Closed-Loop models are best installed near the equipment exhaust; Open-Loop models at the air inlet.
2. Air temperature of 70 °C or less. Minimum air velocity of 200 ft/min.

Additional Information

» Wisp II Operation / Installation Datasheet (PDF)
» Wisp STEP CAD drawing (.stp)
NOTE: If the CAD file opens as a new browser window with text, right click the link, select “Save Link As”, and select a local folder to save the file.
» SmartFan Price List (PDF)
» Click here for Questions or Comments

To talk to an Engineer or Service Representative, call (978) 486-4160 (9:00 AM – 5:00 PM EST)

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Initially designed for our own engineering lab, CRI also offers versatile, low-cost test equipment for test benches, laboratories, field work, and repair facilities.