Detector for shorted rotating diode of a brushless alternator

Claim 2

In a brushless alternator having an exciter field circuit including a source of DC potential with a reference, a stationary exciter field winding and a voltage regulator transistor connected in series with the field winding across the DC source, a rotor with an exciter armature, a diode rectifier connected with said armature and a main field winding connected with the diode rectifier, a stator winding in which the alternator output voltage is developed coupled with the main field winding, and a voltage regulator responsive to the alternator output providing a base drive signal to the voltage regulator transistor, an improved detector for a shorted diode rectifier, comprising: means for comparing the voltage at the base of the voltage regulator transistor and the voltage at the terminal of said stator field winding connected with said voltage regulator transistor; and means responsive to the comparing means for indicating the occurrence of a shorted diode rectifier on said rotor.

Claim 3

The shorted diode rectifier detector of claim 1 in which the voltage at said stator field winding terminal is of the order of the DC source reference in the absence of a voltage at the voltage regulator transistor base, indicating occurrence of a shorted diode rectifier.

Claim 4

The shorted diode rectifier detector of claim 2 in which said responsive means is a gate circuit having the voltage regulator transistor base voltage connected with one input and the stator field winding terminal voltage connected with another input.

Claim 5

The shorted diode rectifier detector of claim 1 including: a first inverter connected with the stator field winding terminal; a second inverter connected with the voltage regulator transistor base; and an AND gate having two inputs, one connected with the output of each of said inverters, the output of the AND gate being high upon occurrence of a shorted diode rectifier.

Claim 6

In a brushless alternator having an exciter field winding, a rotor with an exciter armature, a diode rectifier connected with the armature and a main field winding connected with the rectifier, a stator winding in which the alternator output voltage is developed, coupled with said main field winding and a voltage regulator responsive to the alternator output providing a field current control signal, a field circuit with a detector for a shorted diode rectifier, comprising: a DC power source with a reference; a voltage regulator transistor having a collector-emitter circuit connected in series with said exciter field winding across said DC potential source, and a base element connected with said voltage regulator to respond to said field current control signal; means for comparing the voltage at the base of the voltage regulator transistor and the voltage at the terminal of said stator field winding connected with the emitter-collector circuit of said voltage regulator transistor; and means responsive to the comparing means for indicating the occurrence of a shorted diode rectifier.

Claim 7

In a brushless alternator having an exciter field winding, a rotor with an exciter armature, a diode rectifier connected with the armature and a main field winding connected with the rectifier, a stator winding in which the alternator output voltage is developed, coupled with said main field winding and a voltage regulator responsive to the alternator output providing a field current control signal, a field circuit with a detector for a shorted diode rectifier, comprising: a DC power source with a reference; a voltage regulator transistor having a collector-emitter circuit connected in series with said exciter field winding across said DC potential source, and a base element connected with said voltage regulator to respond to said field current control signal; means for comparing the voltage at the base of the voltage regulator transistor and the voltage at the terminal of said stator field winding connected with the emitter-collector circuit of said voltage regulator transistor; and means responsive to the comparing means for indicating the occurrence of a shorted diode rectifier.

Claim 8

The shorted diode rectifier detector of claim 5 in which the voltage at said stator field winding terminal is of the order of the DC source reference in the absence of a voltage at the voltage regulator transistor base, indicating occurrence of a shorted diode rectifier.

Claim 9

The field circuit of claim 6 including a diode connected in parallel with the collector-emitter circuit of said voltage regulator transistor and poled to conduct a current of opposite polarity to the current conducted through said transistor.

Claim 10

The exciter field circuit of claim 6 including a diode connected across said field winding and poled to conduct current from the field winding upon termination of a field current control signal to the base element of the voltage regulator transistor.

Claim 11

The alternator field circuit of claim 6 including a capacitor connected across said DC power source.

Claim 12

The alternator field circuit of claim 6 including: a capacitor connected across said DC power source; a diode connected in parallel with the collector-emitter circuit of said voltage regulator transistor and poled to conduct a current of opposite polarity to the current conducted through said transistor; and a diode connected across said field winding and poled to conduct current from the field winding upon termination of a field current control signal to the base element of the voltage regulator transistor.

Claim 13

In a brushless alternator having an exciter field circuit including a source of DC potential with a reference, a voltage regulator transistor and a stationary exciter field winding having one terminal connected with the DC source and the other terminal connected in series with the collector-emitter circuit of the voltage regulator transistor to the DC source reference, a rotor with an exciter armature, a diode rectifier connected with said armature and a main field winding connected with the diode rectifier, a stator winding coupled with the main field winding and in which the alternator output voltage is developed, and a voltage regulator responsive to the alternator output to control the voltage regulator transistor, an improved detector for a shorted diode rectifier, comprising: a comparator responsive to the occurrence of a voltage at the other terminal of the stator field winding of the order of the DC reference voltage in the absence of a voltage regulator transistor base drive signal, for detecting a shorted rotating diode condition.

Claim 14

In a brushless alternator having an exciter field circuit including a source of DC potential with a reference, a voltage regulator transistor and a stationary exciter field winding having one terminal connected with the DC source and the other terminal connected in series with the collector-emitter circuit of the voltage regulator transistor to the DC source reference, a rotor with an exciter armature, a diode rectifier connected with said armature and a main field winding connected with the diode rectifier, a stator winding coupled with the main field winding and in which the alternator output voltage is developed, and a voltage regulator responsive to the alternator output to control the voltage regulator transistor, an improved detector for a shorted diode rectifier, comprising: a comparator responsive to the occurrence of a voltage at the other terminal of the stator field winding of the order of the DC reference voltage in the absence of a voltage regulator transistor base drive signal, for detecting a shorted rotating diode condition.

Claim 15

In a brushless alternator having an exciter field winding, a rotor with an exciter armature, a diode rectifier connected with the armature and a main field winding connected with the rectifier, a stator winding in which the alternator output voltage is developed, coupled with said main field winding and a voltage regulator responsive to the alternator output providing a field current control signal, a field circuit with a detector for a shorted diode rectifier, comprising: a DC power source with a reference; a voltage regulator transistor having a collector-emitter circuit connected in series with said exciter field winding across said DC potential source, and a base element connected with said voltage regulator to respond to said field current control signal; a capacitor connected across said DC power source; a diode connected in parallel with the collector-emitter circuit of said voltage regulator transistor and poled to conduct a current of opposite polarity to the current conducted through said transistor; and a comparator responsive to the occurrence of voltage, at the stator field winding terminal connected with the collector-emitter circuit of the voltage regulator transistor of the order of the DC reference voltage in the absence of a base drive signal to the voltage regulator transistor, for detecting a shorted rotating diode condition.

Claim 16

In a brushless alternator having an exciter field winding, a rotor with an exciter armature, a diode rectifier connected with the armature and a main field winding connected with the rectifier, a stator winding in which the alternator output voltage is developed, coupled with said main field winding and a voltage regulator responsive to the alternator output providing a field current control signal, a field circuit with a detector for a shorted diode rectifier, comprising: a DC power source with a reference; a voltage regulator transistor having a collector-emitter circuit connected in series with said exciter field winding across said DC potential source, and a base element connected with said voltage regulator to respond to said field current control signal; a capacitor connected across said DC power source; a diode connected in parallel with the collector-emitter circuit of said voltage regulator transistor and poled to conduct a current of opposite polarity to the current conducted through said transistor; and a comparator responsive to the occurrence of voltage, at the stator field winding terminal connected with the collector-emitter circuit of the voltage regulator transistor of the order of the DC reference voltage in the absence of a base drive signal to the voltage regulator transistor, for detecting a shorted rotating diode condition.