Apparatus and method for detecting fault of cooling fan

Abstract

An apparatus for detecting a fault of a cooling fan includes an electronic switch connected to a negative (−) power input terminal of a cooling fan and turning on/off the cooling fan; a current detector connected to the electronic switch and detecting a current value of the cooling fan; an analog filter for filtering the detected current value; and a controller for converting the filtered current value into a digital current value and determining whether the cooling fan is improperly operated based on the converted digital current value and a pre-set upper threshold value and lower threshold value.

1 . An apparatus for detecting a fault of a cooling fan comprising: 
 an electronic switch connected to a negative (−) power input terminal of a cooling fan and turning on/off the cooling fan;    a current detector connected to the electronic switch and detecting a current value of the cooling fan;    an analog filter for filtering the detected current value; and    a controller for converting the filtered current value into a digital current value and determining whether the cooling fan is improperly operated based on the converted digital current value and a pre-set upper threshold value and lower threshold value.    
   
   
       2 . The apparatus of  claim 1 , further comprising: 
 a freewheeling diode connected between the positive (+) power input terminal and the negative (−) power input terminal of the cooling fan and annihilating a field current of the cooling fan.    
   
   
       3 . The apparatus of  claim 1 , wherein the controller includes an A/D converter for converting the filtered current value into a digital current value.  
   
   
       4 . The apparatus of  claim 3 , wherein the controller includes a memory for storing the upper and lower threshold values.  
   
   
       5 . The apparatus of  claim 4 , wherein the upper threshold value is previously set based on current values detected when the cooling fan is not operated.  
   
   
       6 . The apparatus of  claim 4 , wherein the lower threshold value is previously set based on current values detected when the cooling fan is not connected to a power source.  
   
   
       7 . A method for detecting a fault of a cooling fan comprising: 
 detecting a current value applied to a cooling fan and converting it into a digital current value;    comparing the converted digital current value with an upper threshold value;    comparing the digital current value with a lower threshold value when the converted digital current value is smaller than the upper threshold value; and    normally driving the cooling fan when the converted digital current value is greater than the lower threshold value.    
   
   
       8 . The method of  claim 7 , further comprising: 
 measuring the upper and lower threshold values according to the cooling fan and storing the measured values.    
   
   
       9 . The method of  claim 8 , wherein the upper threshold value is previously set based on current values detected when the cooling fan is not operated.  
   
   
       10 . The method of  claim 8 , wherein the lower threshold value is previously set based on current values detected when the cooling fan is not connected to a power source.  
   
   
       11 . The method of  claim 7 , further comprising: 
 informing a user that the cooling fan is not properly operated when the converted digital current signal is greater than the upper threshold value.    
   
   
       12 . The method of  claim 7 , further comprising: 
 informing a user that the cooling fan is not properly operated when the converted digital current signal is smaller than the lower threshold value.