Standby generator pulse excitation system and electric power generating system for use therein

Claim 1

A back-up electric power generating system, comprising: a first variable speed synchronous generator drivably coupled to a first prime mover, said first generator having an exciter field, a rotor, and a poly-phase wound stator forming a first output, said first generator producing a voltage signal on said first output in response to a current signal applied to said exciter field; a second variable speed synchronous generator drivably coupled to a second prime mover, said second generator having an exciter field, a rotor, and a poly-phase wound stator forming a second output, said second generator producing a voltage signal on said second output in response to a current signal applied to said exciter field; a converter having a first and a second input coupled to said first and said second generators respectively, and an output; logic means in controlling communication with said converter for designating one of said first or said second generators as a primary power source and one of said first or said second generators as a standby power source, exclusively; means selectably coupled to said exciter field of said primary power source and in controlled communication with said logic means for regulating output voltage of said primary power source, said regulating means generating a controlled current signal to maintain said output voltage at a given level thereby; means selectably coupled to said exciter field of said standby power source and in controlled communication with said logic means for verifying the operational readiness of said standby power source, said verifying means generating a current pulse signal to said exciter field of said standby power source and monitoring said output voltage generated thereby; and wherein said converter produces a constant frequency voltage on said converter output in response to a voltage signal from said primary power source.

Claim 12

A method of providing a verifiable third source of electric power on a two engine aircraft, the third source having a first variable speed generator drivably coupled to a first prime mover, the first generator having an exciter field, a rotor, and a poly-phase wound stator forming a first output, a second variable speed synchronous generator drivably coupled to a second prime mover, the second generator having an exciter field, a rotor, and a poly-phase wound stator forming a second output, and a converter having a first and a second input coupled to the first and the second generators respectively, and an output, comprising the steps of: designating one of the first or the second generators as a primary power source and one of said first or said second generators as a standby power source, exclusively; generating a controlled current signal to the exciter field of the generator designated as the primary power source to maintain its output voltage at a given level; generating a current pulse signal to the exciter field of the generator designated as the standby power source; monitoring the output of the standby power source; indicating the operational status of the standby power source as ready upon detecting a voltage pulse on the output of the standby power source generated in response to the current pulse, or as not ready upon detecting the lack of a voltage pulse on the output of the standby power source in response to the current pulse; and converting the output voltage of the primary power source into a constant frequency voltage.

Claim 13

A method of providing a verifiable third source of electric power on a two engine aircraft, the third source having a first variable speed generator drivably coupled to a first prime mover, the first generator having an exciter field, a rotor, and a poly-phase wound stator forming a first output, a second variable speed synchronous generator drivably coupled to a second prime mover, the second generator having an exciter field, a rotor, and a poly-phase wound stator forming a second output, and a converter having a first and a second input coupled to the first and the second generators respectively, and an output, comprising the steps of: designating one of the first or the second generators as a primary power source and one of said first or said second generators as a standby power source, exclusively; generating a controlled current signal to the exciter field of the generator designated as the primary power source to maintain its output voltage at a given level; generating a current pulse signal to the exciter field of the generator designated as the standby power source; monitoring the output of the standby power source; indicating the operational status of the standby power source as ready upon detecting a voltage pulse on the output of the standby power source generated in response to the current pulse, or as not ready upon detecting the lack of a voltage pulse on the output of the standby power source in response to the current pulse; and converting the output voltage of the primary power source into a constant frequency voltage.