Variable Speed Fan Drives

Designed to cool the new hotter-running reduced emission engines, this revolutionary directly controlled viscous fan drive can be managed by the engine’s electronic control unit for precision fan speed control. Its innovative reservoir, actuator and valve system deliver faster response time and lower off speed for maximum efficiency. The result is reduced fan noise and fuel savings.

Stratis is equipped with a rear mounted cable harness and the fan is uniquely installed on the front of the fan drive to increase airflow and improve cooling. The integral fan speed sensor provides close loop control. An optimized magnetic design speeds up reaction time for better modulation and cooling. Plus, the fan drive’s housing and cover have optimized fins to provide greater heat dissipation.


  • Rapid fan speed
  • More available horsepower
  • Less fuel consumption
  • Lighter and more powerful
  • Increased durability and longer product life
  • No maintenance
  • Exceptional value


  • Fan speed engages and disengages within seconds for precision cooling and optimum efficiency
  • Standard idle speed 250 rpm or lower depending on application
  • Compact with greater torque
  • Double-row bearing
  • Completely sealed durable construction
  • Rear electrical connection harness
  • Optimized fluid flow return path


  • Heavy-duty trucks
  • Medium-duty trucks
  • Transit buses
  • Motor coaches
  • Off-highway equipment
Maximum torque: 2,225 in.-lbs. [250 N-m]
Fan blade capacity: Up to 11 blades. 32 in. [812.8 mm] diameter

Related Products

  • VMaster® Air-Sensing Fan Drives
  • VMaster Directly Controlled Fan Drives
  • WindMaster Fans


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