Control unit for an electric motor, in particular fora fan motor

Abstract

The invention provides a control unit for at least one electric motor, wherein the control unit performs open-loop or closed-loop control of the motor speed of the electric motor in such a way that in the case of control values in specific ranges which are typical of a fault when the setpoint value is being predefined, such a fault being, for example, a line break, a voltage failure or a short circuit, the control unit drives the motor with a predefined setpoint value which differs from the current control value.

1 - 14 . (canceled) 
     
     
         15 . A cooling fan, comprising:
 a housing;   a brushless DC motor mounted in the housing;   a fan wheel operatively engaged with a rotor of the brushless DC motor, wherein the fan wheel is adapted to rotate when the brushless DC motor is operated in order to create a flow of cooling air;   a motor controller mounted in the housing in a fixed relationship with the brushless DC motor, wherein the motor controller is adapted (a) to cause the rotor and the fan wheel to rotate at a nonzero speed if the magnitude of a control signal is in a range of values associated with a fault condition and (b) to stop rotation of the rotor and the fan wheel if the control signal is between a nonzero first threshold value and a second threshold value greater than the first threshold value.   
     
     
         16 . The cooling fan of  claim 15 , wherein the range of values associated with the fault condition is a range from zero to the first threshold value. 
     
     
         17 . The cooling fan of  claim 15 , wherein the control signal is one of a pulse-width modulated signal and a voltage. 
     
     
         18 . The cooling fan of  claim 15 , wherein control signal is an analog voltage signal. 
     
     
         19 . The cooling fan of  claim 18 , wherein the range of values associated with a fault condition includes a value that represents one of zero volts and a voltage identical to a supply voltage. 
     
     
         20 . The cooling fan of  claim 15 , wherein the control signal is a modulated signal and the range of values associated with a fault includes a value associated with a signal modulated 0% and a value associated with a signal modulated 100%. 
     
     
         21 . The cooling fan of  claim 15 , comprising an analog-to-digital converter adapted to convert an analog control signal into a digital control signal. 
     
     
         22 . The cooling fan of  claim 15 , wherein the first threshold value is one of 0.5 volts and 5% modulation. 
     
     
         23 . The cooling fan of  claim 22 , wherein the second threshold value is one of 1 volt and 10% modulation. 
     
     
         24 . The cooling fan of  claim 23 , comprising a further circuit to generate a warning signal if the control value indicates a fault. 
     
     
         25 . The cooling fan of  claim 24 , wherein the further circuit generates one of a visual warning signal, an audible warning signal, and a combination thereof.