Method of providing overvoltage protection

Abstract

A controller for a starter.generator used with an aircraft engine, includes means for monitoring field return current in a generator field winding; means for monitoring generator voltage; and microprocessor control means for adjusting generator field current as a function of the field current and voltage and field return current. The field return current and output voltage monitoring functions allow for open field, field integrity, over voltage, field weakening and torque limiting functions to be realized in an integrated programmable system configuration.

What is claimed is:  
     
         1 . Apparatus for detecting a generator overvoltage condition, comprising: 
 sensing means for detecting generator output voltage;    a voltage regulator circuit utilizing the generator's output voltage for input and producing an output comprising a status signal corresponding to the generator's operating mode, microprocessor control means for detecting an overvoltage condition from said sensing means, and means for monitoring the voltage regulator's status signal, said microprocessor control means causing the generator to de-energize if an overvoltage condition exists and the status signal of the voltage regulator remains on.    
     
     
         2 . Apparatus for detecting a generator overvoltage condition, comprising: 
 a sensing means for detecting generator output voltage;    a voltage regulator circuit utilizing the generator's output voltage for input and producing an output comprising a status signal corresponding to the generator's operating mode, microprocessor control means for detecting an overvoltage condition from said sensing means, and means for monitoring the voltage regulator's status signal, wherein said monitoring means comprises a free wheeling diode in shunt with the generator field winding, and means for detecting current flow through said diode, said microprocessor control means causing the generator to de-energize if an overvoltage condition exists and the status signal of said sensing means remains on.