Dehydration control method of drum washing machine

Abstract

In a dehydration control method of a drum washing machine capable of improving reliability of eccentricity sensing by sensing not only forward eccentricity but also diagonal eccentricity by performing eccentricity sensing at a low speed and a high speed respectively, the method includes a first step for accelerating a drum to a first rotational speed when a uniforming process is finished; a second step for measuring first eccentricity when the rotational speed of the drum reaches the first rotational speed; a third step for comparing the measured first eccentricity with a preset first reference eccentricity; a fourth step for storing the measured first eccentricity when the measured first eccentricity is less than the preset first reference eccentricity in the third step; a fifth step for accelerating the rotational speed of the drum to a second rotational speed and measuring a second eccentricity when it reaches the second rotational speed; a sixth process for comparing the measured second eccentricity with the stored first eccentricity; and a seventh step for performing a dehydrating process when the measured second eccentricity is less than the stored first eccentricity.

1 . A dehydration control method of a washing machine, comprising: 
 accelerating a drum to a first rotational speed after a uniforming process;    changing the drum speed to a second rotational speed; and    continuing the dehydration process after maintaining the second rotational speed for a preset period.    
   
   
       2 . The dehydration control method according to  claim 1 , wherein the uniforming is performed within a range of about 50-58 RPM.  
   
   
       3 . The dehydration control method according to  claim 1 , wherein the first rotational speed is within a range of about 100-108 RPM.  
   
   
       4 . The dehydration control method according to  claim 1 , wherein the second rotational speed is about 180 RPM.  
   
   
       5 . A dehydration control method of a washing machine, comprising: 
 accelerating a drum to a first rotational speed after a uniforming process;    maintaining the first rotational speed for a preset period;    changing the drum speed to a second rotational speed; and    continuing the dehydration process after maintaining the second rotational speed for a preset period.    
   
   
       6 . The dehydration control method according to  claim 5 , wherein the uniforming is performed within a range of about 50-58 RPM.  
   
   
       7 . The dehydration control method according to  claim 5 , wherein the first rotational speed is within a range of about 100-108 RPM.  
   
   
       8 . The dehydration control method according to  claim 5 , wherein the second rotational speed is about 180 RPM.  
   
   
       9 . A dehydration control method of a washing machine, comprising: 
 accelerating a drum to a first rotational speed after a uniforming process;    maintaining the first rotational speed for a preset period;    judging if an eccentricity of laundry exceeds a permitted limit at the first speed;    changing the drum speed to a second rotational speed when the eccentricity is within the limit; and    continuing the dehydration process after maintaining the second rotational speed for a preset period.    
   
   
       10 . The dehydration control method according to  claim 9 , wherein the eccentricity is obtained by measuring RPM variation of the driving motor with an RPM sensing unit installed at a driving motor of the drum.  
   
   
       11 . The dehydration control method according to  claim 9 , further comprising: 
 stopping and re-accelerating the drum speed when the eccentricity of laundry exceeds a permitted limit at the first speed    
   
   
       12 . A dehydration control method of a washing machine, comprising: 
 accelerating a drum to a first rotational speed after a uniforming process;    maintaining the first rotational speed for a preset period;    changing the drum speed to a second rotational speed;    maintaining the second rotational speed for a preset period;    judging if an eccentricity of laundry exceeds a permitted limit at the second speed; and    continuing the dehydration process after maintaining the second rotational speed for the preset period.    
   
   
       13 . The dehydration control method according to  claim 12 , wherein the eccentricity is obtained by measuring RPM variation of the driving motor with an RPM sensing unit installed at a driving motor of the drum.  
   
   
       14 . The dehydration control method according to  claim 12 , further comprising: 
 stopping and re-accelerating the drum speed when the eccentricity of laundry exceeds a permitted limit at the second speed    
   
   
       15 . The dehydration control method according to  claim 12 , further comprising: 
 changing the drum speed to the first speed if the eccentricity of laundry exceeds a permitted limit at the second speed.    
   
   
       16 . A dehydration control method of a washing machine, comprising: 
 accelerating a drum to a first rotational speed after a uniforming process;    maintaining the first rotational speed for a preset period;    judging if an eccentricity of laundry exceeds a permitted limit at the first speed;    changing the drum speed to a second rotational speed when the eccentricity is within the limit;    maintaining the second rotational speed for a preset period;    judging if an eccentricity of laundry exceeds a permitted limit at the second speed; and    determining if the dehydration process is continued at the second speed.    
   
   
       17 . The dehydration control method according to  claim 16 , wherein the eccentricity is obtained by measuring RPM variation of the driving motor with an RPM sensing unit installed at a driving motor of the drum.  
   
   
       18 . The dehydration control method according to  claim 16 , further comprising: 
 stopping and re-accelerating the drum speed when the eccentricity of laundry exceeds a permitted limit at the first speed    
   
   
       19 . The dehydration control method according to  claim 16 , further comprising: 
 stopping and re-accelerating the drum speed when the eccentricity of laundry exceeds a permitted limit at the second speed    
   
   
       20 . The dehydration control method according to  claim 16 , further comprising: 
 changing the drum speed to the first speed if the eccentricity of laundry exceeds a permitted limit at the second speed.    
   
   
       21 . The dehydration control method according to  claim 16 , further comprising: 
 maintaining the first rotational speed for a preset period;    judging if an eccentricity of laundry exceeds a permitted limit at the first speed; and    changing the drum speed to a second rotational speed when the eccentricity is within the limit.