Self-cleaning condenser

Abstract

An air conditioning system includes a condenser coil and a fan situated adjacent the condenser coil. The fan driven by a motor, which is reversed to change the rotational direction of the fan in response to a predetermined condition. The fan is operated in a first direction to cool a condenser coil, and reversed to blow away collected debris, thus cleaning the condenser coil. The fan is reversed in response to one or more predetermined conditions.

1 . A method of operating a condenser fan, comprising: 
 operating the fan in a first direction to cool a condenser coil; and    operating the fan in a second direction for a predetermined time period to clean the condenser coil.    
   
   
       2 . The method of  claim 1 , wherein operating the fan in the second direction includes operating the fan in the second direction in response to a predetermined condition.  
   
   
       3 . The method of  claim 2 , wherein the predetermined condition includes a predetermined time.  
   
   
       4 . The method of  claim 2 , wherein the predetermined condition includes ambient temperature.  
   
   
       5 . The method of  claim 2 , wherein the predetermined condition includes pressure.  
   
   
       6 . The method of  claim 2 , wherein a compressor is connected to the condenser coil, and wherein the predetermined condition includes the compressor turning off.  
   
   
       7 . The method of  claim 2 , further comprising monitoring torque of a motor driving the fan, wherein the predetermined condition includes the torque.  
   
   
       8 . The method of  claim 1 , wherein the fan is driven by a three-phase motor, and wherein operating the fan in the second direction includes reversing two of the three motor phases.  
   
   
       9 . The method of  claim 1 , wherein the fan is driven by a single-phase motor having a motor capacitor, and wherein operating the fan in the second direction includes reversing line and neutral connections to the motor capacitor.  
   
   
       10 . An air conditioning system, comprising: 
 a condenser coil;    a fan situated adjacent the condenser coil, the fan driven by a motor;    a motor controller programmed to operate the fan in a first rotational direction to cool the condenser coil and to reverse the rotational direction of the fan for a predetermined time period in response to a predetermined condition.    
   
   
       11 . The air conditioning system of  claim 10 , wherein the motor controller reverses the rotational direction of the fan at a predetermined time.  
   
   
       12 . The air conditioning system of  claim 10 , further comprising a temperature measurement device, wherein the motor controller reverses the rotational direction of the fan in response to the temperature measurement.  
   
   
       13 . The air conditioning system of  claim 12 , wherein the motor controller reverses the rotational direction of the fan in response to the temperature being below a predetermined level.  
   
   
       14 . The air conditioning system of  claim 10 , wherein the motor controller monitors motor torque, and wherein the motor controller reverses the rotational direction of the fan in response to the torque.  
   
   
       15 . The air conditioning system of  claim 10 , further comprising a compressor connected to the condenser coil, wherein the predetermined condition includes the compressor turning off.  
   
   
       16 . The air conditioning system of  claim 10 , wherein the airflow created by the fan is generally horizontal.  
   
   
       17 . The air conditioning system of  claim 10 , wherein the airflow created by the fan is generally vertical.  
   
   
       18 . The air conditioning system of  claim 10 , wherein the motor is a three-phase motor, and wherein the motor controller reverses two of the three phases to reverse the rotational direction of the fan.  
   
   
       19 . The air conditioning system of  claim 10 , wherein the motor is a single-phase motor, and wherein the motor controller reverses line and neutral connections to the motor capacitor to reverse the rotational direction of the fan.