Control scheme for a roof vent fan assembly

Abstract

A method is provided for controlling a roof vent fan assembly having a fan motor operably coupled to a fan. The method comprises: monitoring an operating condition of the fan motor; detecting a jam condition of the fan based on the operating condition of the fan motor; and, upon detecting the jam condition, stopping operation of the fan motor and subsequently restarting operation of the fan motor.

1 . A method for controlling a roof vent fan assembly having a fan motor operably coupled to a fan, comprising: 
 monitoring current of a control signal driving the fan motor;    monitoring a voltage of a power source providing the control signal for the fan motor;    determining a wattage associated with the fan motor based on the current and the voltage;    detecting a jam condition of the fan based on the wattage associated with the fan motor; and    controlling operation of the fan motor upon detecting the jam condition.    
   
   
       2 . The method of  claim 1  further comprises detecting a jam condition of the fan when the wattage exceeds a threshold value.  
   
   
       3 . The method of  claim 1  further comprises detecting a jam condition of the fan when the wattage is below a minimum value.  
   
   
       4 . The method of  claim 1  wherein said controlling comprises stopping the operation of the fan motor and subsequently restarting operation of the fan motor.  
   
   
       5 . The method of  claim 4  wherein said controlling comprises stopping the operation of the fan motor for a predetermined time period and subsequently restarting the fan motor at an increased speed after the predetermined time period has expired.  
   
   
       6 . The method of  claim 5  further comprises repeating said monitoring current, said monitoring a voltage, determining a wattage, and said controlling operation of the fan until a jam condition is no longer detected.  
   
   
       7 . The method of  claim 5  further comprises: 
 repeating said monitoring current, said monitoring a voltage, said determining a wattage, and said controlling operation of the fan a selectable number of times; and    wherein if a jam condition is detected each time of the selectable number of times, commanding the fan motor off.    
   
   
       8 . The method of  claim 6  further comprises determining the time period based on a number of occurrences a jam condition is detected.  
   
   
       9 . The method of  claim 1  further comprises, commanding a notification signal upon detecting the jam condition, wherein the notification signal illuminates an indicator light.  
   
   
       10 . The method of  claim 1  further comprises, commanding a notification signal upon detecting the jam condition, wherein the notification signal activates an audio warning device.  
   
   
       11 . A method of controlling a roof vent fan assembly having a fan motor operably coupled to a fan, comprising: 
 monitoring an operating condition of the fan motor;    detecting a jam condition of the fan based on the operating condition of the fan motor; and    upon detecting the jam condition, stopping operation of the fan motor and subsequently restarting operation of the fan motor.    
   
   
       12 . The method of  claim 11  further comprises monitoring current of a control signal driving the fan motor and detecting a jam condition of the fan based on the current.  
   
   
       13 . The method of  claim 11  further comprises monitoring voltage of a power source providing a control signal driving the fan motor and detecting a jam condition of the fan based on the current.  
   
   
       14 . The method of  claim 11  further comprises: 
 monitoring current of a control signal driving the fan motor;    monitoring voltage of a power source providing the control signal for the fan motor;    determining a wattage associated with the fan motor based on the current and the voltage; and    detecting a jam condition of the fan based on the wattage associated with the fan motor.    
   
   
       15 . The method of  claim 11  further comprises restarting operation of the fan motor at a fan speed higher than a fan speed at which the fan was being operated when the jam condition occurred.  
   
   
       16 . The method of  claim 15  further comprises repeating said stopping and said restarting until a jam is not detected.  
   
   
       17 . The method of  claim 15  further comprises repeating said stopping and said restarting for a selectable number of times, and if each time of the selectable number of times a jam condition is detected, turning the fan motor off.  
   
   
       18 . The method of  claim 17  further comprises turning the fan motor back on if a fan on signal is received from a wall controller and a jam is not detected.  
   
   
       19 . The method of  claim 11  further comprises commanding a notification signal upon detecting the jam condition, wherein the notification signal illuminates an indicator light.  
   
   
       20 . The method of  claim 11  further comprises commanding a notification signal upon detecting the jam condition, wherein the notification signal activates an audio warning device.