AC/DC Fan control

Fan motors are characterized by their electrical configuration (2 to 4-wire), their DC or AC input, and their speed regulating features.

  • 2-wire fans/motors are basic DC fans/motors with positive and negative power leads. Fan 2-wire controls regulate fan/motor speed by varying the voltage to the fan/motor. Several of our fan models offer an additional temperature alarm output. Multiple fans/motors can be connected in parallel up to the current rating of the model.
  • 3-wire fans/motors include a tach pulse or alarm (rotation/locked rotor) lead in addition to the positive and negative power leads. Fan 3-wire controls regulate fan/motor speed and monitor tach pulses to provide pass/fail signals. Some 3-wire fans have an alarm output for the third lead instead of a tach pulse.
  • 4-wire fans/motors have a speed control lead as a fourth wire. Fan 4-wire controls pass the supply voltage directly to the fan/motor, and then regulate fan speed by providing a control signal. The controls monitor the tach pulses from the fans/motors and provide pass/fail signals.
  • In case of a regulated supply voltage in the enclosure, the speed of the fan/motor can be adjusted by the speed control signal eliminating the need for a buck or buck/boost voltage regulator on the control board.
  • A 2-wire or 3-wire fan/motor can typically operate down to about ½ speed without concern for the fan/motor stalling. A 4-wire fan/motor can be operated at less than ½ speed and can even be turned off using the speed control signal.
    These fans are also offered with significantly higher performance features (RPM, pressure, flow) when compared with standard 2- and 3-wire fans.


Fan tray design

To respond to challenging cooling requests by our partners for enclosures and chassis for telecoms application, a fan tray can be custom designed and produced. These fan trays most demanding feature resides in the electronics for fan speed control and monitoring, as well as for reporting ( local and remote )_ on the tray operating status. With our vast experience of design, engineering, assemble and test for our families of enclosures and chassis, Asis Pro can handle all our partners’ requirements, providing:

  • One-stop shop: Prototype to volume production
  • Multiple fan sourcing to meet specifications
  • Test and approval capabilities.

Fan failure alarms

Fan speed control board can issue and transmit alarm and warnings to prevent heat damage to the embedded computing enclosures, chassis and installed boards by reporting on fan failure or malfunction.

Custom fan speed control

To meet a wide variety of Comms applications, Asis-Pro has developed a line of off the shelf fan speed controllers (AC or DC). However, in response to demanding specifications by our partners, several custom solutions have been designed and produced with key characteristics, as follows:

  • Idle speed
  • Sensitivity (by means of control slope)
  • Control sensor input (temperature, pressure, humidity and more)
  • Trigger points for warnings and alarms
  • Signal output of alarm
  • Communication – I2C or MODBUS
  • Remote access – optional
  • Vibration isolation
  • In rush current control
  • Start-up current control.
  • Independent or common FAN control – optional