SmartFan® Stratus II – Variable Frequency Drive / VFD

  • VFD Control for Single & Three Phase Motors

  • 7 Programmable Control Modes & 18 Programmable Variables

  • PID Plus programming for constant pressure or flow

  • $126 each for 50 Piece orders – as low as $98 in Volume

Operation / Installation PDF

Stratus II Datasheet

SmartFan Stratus II VFD (variable frequency drive) is designed to control single or three-phase fractional HP, inverter grade motors via a transducer (voltage or current signal), building automation system (voltage, current signal, Modbus), thermistor, potentiometer, contact closure or Modbus RTU network.  This VFD can be customized in minutes using the menu driven SmartFan Navigator handheld remote programmer or through the Modbus communications port.

Economical OEM pricing as low as $126 for 50 pieces – under $100 in higher volumes.

For an explanation of the Stratus II variable frequency drive motor requirements and risks, please see: AC Motor Compatibility

For a technical article on how the Stratus II AC variable frequency drive compares to other control technologies, see: Controller Comparison & Motor Efficiency

Specifications Features / Selectable Options
  • » Input Power: 115 / 240 VAC, 47-64 Hz, single phase, 5.7A
  • » Output Power: 115 / 240 VAC, 0-400 Hz, single phase or 3-phase, 4A
  • » For use with inverter grade motors
  • » Accessory Output: 5VDC @ 50mA
  • » Control Options:
    • – 0-5VDC or 0-10VDC
    • – 4-20mA
    • PID Plus (constant pressure, constant flow…)
    • – Potentiometer
    • – Temperature (thermistor)
    • – Transducer
    • – Modbus
    • – Fixed Speed
  • » Operation Temperature: -20°C to 40°C
  • » Storage Temperature: -40°C to 125°C
  • » Relative Humidity: 95% non-condensing
  • » Weight: VFD400E-F – 32oz (905g); VFD400-F – 22oz (625g)
  • » UL and RoHS compliant
  • recognized to UL508C, File E331664
  • » Three programming options:
    • – SmartFan Navigator PRG02-F handheld remote
    • – Windows PC USB port using a Modbus master application
    • – Factory customization and programming for orders as small as 50 pieces
  • » Programmable variables include:
    • – Control slope, 4 variables including on/off at idle
    • – Alarm trigger point and direction
    • – Ramp up and ramp down rates
    • – Programmable current limit up to 10 Amps
    • – PWM frequency
    • – Motor frequency and direction
    • – Contact closure polarity and frequency
  • » Over temperature protection
  • » Available with or without metal safety enclosure
  • » Contact closure allows settable on/off override option
  • » On-board status LEDs
  • » Warranty: 2 years
  • » Made in the USA

Stratus II VFD Dimensions


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

Stratus II VFD Part Numbers

Part No. Description
VFD400E-F Stock Product, includes metal safety enclosure
VFD400-F No enclosure (10 piece minimum order)
VFD401E-F MODBUS, Contact Closure and Fixed speed inputs only, includes metal safety enclosure (10 piece minimum order)
VFD401-F MODBUS, Contact Closure and Fixed speed inputs only, no enclosure (10 piece minimum order)
PRG02-F* Stratus II Navigator remote hand-held programmer (for purchase or rent)
VFD4KIT-F Evaluation kit includes: (1) Stratus II VFD400E-F, (1) Navigator remote programmer PRG02-F, power and motor connection hardware

*Can be used to program Stratus II VFD Rev 4 and higher

Modbus Support Links

» Modbus communications support:

» Modbus master program:

  • – We use ModScan 23 from Win-Tech who offers a free demo version:
  • – Note: this demo is fully functional for one hour and then you have to start it again
» RS232 or USB to RS485 converters

  • – We use B&B Electronics model USOPTL4 for our USB to RS-422/485:
  • – Note: these converters are isolated to protect your equipment
» USB Driver:

Additional Information

» Stratus II Datasheet
» Stratus II IGS CAD drawing (.igs)
» 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.