SmartFan® Multi-SR

     Digital Fan Speed Control and Alarm

SmartFan Multi-SR Digital Fan Speed Control and Alarm

SmartFan Multi-SR Digital Fan Speed Control and Alarm

SmartFan Multi SR is a digital fan speed control and alarm that offers an off-the-shelf OEM control cooling solution for telecommunications applications. Multi SR accepts and diode ORs dual power feeds in the range from 36 to 75 VDC. Multi SR fan speed control can control to up to six 24 or 48 VDC fans and operates at a high frequency to achieve maximum power efficiency at minimum size. Fan speed control can be based on temperature, control signal (PWM, DC) or I2C bus. Voltage to the fans is varied using a common mode buck/boost control circuit. Multi SR monitors tach pulses from the fans and provides OR'd outputs to drive LED, logic and audible alarms. Communication of cooling system status is provided via an I2C bus. Designed with versatility in mind, Multi SR's digital fan speed control and alarm parameters can be modified via on-board jumpers and FLASH microcontroller programming.

In addition to the standard line of SmartFan controls and alarms, Control Resources also provides custom control design and manufacturing services to provide you with the optimum cooling solution for your OEM control applications.

Product Features - SmartFan Multi-SR Digital Fan Speed Control and Alarm

  • Accepts and diode ORs dual power feeds in the range from 36 to 75 VDC
  • Maximum fan current is 4.0 Amps (still air) and 5.0 Amps (200 ft/min air stream) at 55°C
  • Includes soft start and current limiting at start up
  • Supplies voltage to up to six 24 VDC or 48 VDC fans
  • Maximum voltage applied to fans is regulated at 25 VDC for 24 volt fans and 50 VDC for 48 volt fans
  • When used with 48 VDC fans, a boost circuit is included that provides voltages greater than the supply voltage when the supply voltage drops below 48 VDC
  • Monitors open collector or voltage source tach pulses from the fans and provides OR'd outputs to drive LED, logic and audible alarms
  • Additional alarm outputs are provided for multiple failure conditions, over temperature conditions, sensor failure, microcontroller failure and loss of power to the Multi SR
  • Provides communication of cooling system status via an I2C bus
  • Narrow 1.50" width of the board allows for mounting in fan trays as thin as 1U (1.75") high
  • Agency approvals

Selectable Options - SmartFan Multi-SR Digital Fan Speed Control and Alarm

  • Jumpers allow user selectable settings of:
    - Control Temperature
    - Fan Alarm Trigger Speed
    - 24 or 48 VDC Operation
    - Isolated On-Board Power for I2C
  • Accepts temperature (thermistor) inputs from up to three OR'd sensors and provides proportional fan speed control to the fans
  • Fan speed control can also be based on accepting control signals (PWM, DC) or via an I2C bus
  • Sensors
SmartFan Multi-SR Digital Fan Speed Control and Alarm

Part Numbering System - SmartFan Multi-SR Digital Fan Speed Control and Alarm

Part No1 Supply Voltage Range Maximum Watts to Fans2
Number of Fans Number of Temperature Sensors Speed Control Method Isolated 3.3/5.0 VDC Power
200 Ft/Min Still Air
052S4401T06 36 to 75 VDC 240 Watts/5.0 Amps 192 Watts/5.0 Amps 6 1 Remote Temperature Based None Supplied
052S4401T16 Supplied On-Board
H117 Hardware Pack


1. For additional part number options, see table 1 in the Multi-SR Installation & Operation Manual in PDF.

2. Air temperature of 55°C or less. See Derating Curve page for derating above 55°C.

Stock Product
052S4401T06
052S4401T16

U.S. Patents 4,659,290, 4,722,699 and 5,364,026




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