Protective circuit for a voltage regulator

Claim 2

An electrical system comprising, a generator having an output winding an a field winding, a field energizing circuit connected with said output winding including first and second direct current field energizing terminals, a voltage regulator including input and output transistor means, each transistor means comprising at least one transistor, means connecting said field winding and said output transistor means in series across said field energizing terminals whereby field current is controlled by said output transistor means, meaNs connecting the collector and emitter of said input transistor means across the base and emitter of said output transistor means whereby said input transistor means controls the conduction of said output transistor means, means including a voltage reference device connecting said input transistor means with said output winding whereby the conduction of said output transistor means is controlled to maintain a desired regulated output voltage for said generator, a voltage divider including first and second impedances connected across said field energizing terminals, said voltage divider including a junction connected between said impedances the voltage of which varies depending upon the output voltage of said generator, one of said impedances including a temperature dependent resistance which responds to the temperature of said voltage regulator, and a voltage responsive semiconductor including a PN junction having a predetermined forward breakdown voltage connected between said voltage divider junction and one of said field energizing terminals having a lower potential than said junction, said semiconductor connected with said input transistor means and operative to bias said input transistor means on and said output transistor means off when the voltage of said voltage divider junction reaches a predetermined value sufficient to break down said PN junction in a forward direction, said voltage corresponding to an output voltage of said generator which is higher than said desired regulated voltage whereby said voltage divider assumes control of said voltage regulator, one of said impedances having a substantially higher resistance than the other impedance whereby the voltage at said voltage divider junction is reduced in magnitude as compared to the voltage of one of said field energizing terminals to prevent false triggering of said semiconductor by transient voltages.

Claim 3

The electrical system according to claim 1 where the resistance of said one impedance is approximately 30 times the resistance of the other impedance.

Claim 4

The electrical system according to claim 1 where the semiconductor device comprises a PN junction diode connected between said voltage divider junction and the base of said input transistor means, said PN junction diode conducting current in its forward direction between said junction and said base of said input transistor means when its forward conducting voltage is exceeded.

Claim 5

The electrical system according to claim 1 where said semiconductor comprises a transistor having a base connected with said voltage divider junction, a collector connected with the collector of said input transistor means and an emitter connected to the emitter of said input transistor means.

Claim 6

The electrical system according to claim 1 where said semiconductor comprises an NPN transistor having a base connected to said voltage divider junction, a collector connected to the collector of said input transistor means and an emitter connected to the vase of said input transistor means.

Claim 7

An electrical system comprising, a source of voltage including a generator having an output winding and a field winding, a field energizing circuit connected with said output winding including first and second field energizing terminals, a voltage regulator including an output transistor switching means and an input transistor switching means, said output transistor switching means including at least one transistor, said input transistor switching means comprising first and second transistors having a common collector connection with the emitter of said first transistor connected to the base of said second transistor, means connecting said output transistor switching means and said field winding in series across said field energizing terminals, means connecting the collector and emitter of said second transistor across the base and emitter of said output transistor switching means whereby said input transistor switching means controls the conduction of said output trAnsistor switching means, means including a voltage reference device connected with the base of said first transistor and with said output winding for regulating the conduction of said output transistor switching means as a function of the output voltage of said generator to maintain a desired regulated output voltage from said generator, a semiconductor device including a PN junction, a voltage divider including first and second impedances connected across said field energizing terminals having a common junction, means connecting said PN junction and the base-emitter circuit of said second transistor between said junction and one of said field energizing terminals whereby said second transistor is biased conductive when the voltage at said junction reaches a predetermined magnitude which corresponds to an output voltage of said generator which is higher than said desired regulated value, said second impedance connected across said PN junction and the base-emitter circuit of said second transistor having a lower resistance than said first impedance whereby said voltage protection circuit is rendered less sensitive to transient voltages, one of said impedances comprising a temperature dependent resistance means responsive to the temperature of said voltage regulator and operative to vary the voltage between said junction and said one field energizing terminal to correlate this voltage with the changing temperature characteristics of said PN junction and the base-emitter junction of said second transistor.

Claim 8

An electrical system comprising, a source of voltage including a generator having an output winding and a field winding, a field energizing circuit connected with said output winding including first and second field energizing terminals, a voltage regulator including an output transistor switching means and an input transistor switching means, said output transistor switching means including at least one transistor, said input transistor switching means comprising first and second transistors having a common collector connection with the emitter of said first transistor connected to the base of said second transistor, means connecting said output transistor switching means and said field winding in series across said field energizing terminals, means connecting the collector and emitter of said second transistor across the base and emitter of said output transistor switching means whereby said input transistor switching means controls the conduction of said output trAnsistor switching means, means including a voltage reference device connected with the base of said first transistor and with said output winding for regulating the conduction of said output transistor switching means as a function of the output voltage of said generator to maintain a desired regulated output voltage from said generator, a semiconductor device including a PN junction, a voltage divider including first and second impedances connected across said field energizing terminals having a common junction, means connecting said PN junction and the base-emitter circuit of said second transistor between said junction and one of said field energizing terminals whereby said second transistor is biased conductive when the voltage at said junction reaches a predetermined magnitude which corresponds to an output voltage of said generator which is higher than said desired regulated value, said second impedance connected across said PN junction and the base-emitter circuit of said second transistor having a lower resistance than said first impedance whereby said voltage protection circuit is rendered less sensitive to transient voltages, one of said impedances comprising a temperature dependent resistance means responsive to the temperature of said voltage regulator and operative to vary the voltage between said junction and said one field energizing terminal to correlate this voltage with the changing temperature characteristics of said PN junction and the base-emitter junction of said second transistor.

Claim 9

An electrical system comprising, an alternating current generator having an output winding and a field winding, a power bridge rectifier having direct current output terminals connected with said generator, a plurality of auxiliary diodes connected with said output winding, said auxiliary diodes being connected with a third direct current output terminal, said third direct current output terminal and one direct current output terminal of said power bridge rectifier forming field energizing terminals, a voltage regulator including a transistor power output switching means and a transistor input switching means, said output transistor switching means including at least one transistor, said input transistor switching means comprising first and second transistors having a common collector connection with emitter of said first transistor connected to the base of the second transistor, means connecting the collector of said second transistor with the base of said output transistor switching means, means connecting said field winding of said generator and said output transistor switching means in series across said field energizing terminals, means connected with said direct current output terminals of said bridge rectifier and with the base of said first transistor for causing said output transistor switching means to control the field current for said generator as a function of the output voltage of said generator, said last named means operative to maintain the output voltage of said power bridge rectifier at a predetermined desired regulated value, a voltage divider connected across said field energizing terminals including first and second impedances having a common junction, and a semiconductor having a PN junction connected between said voltage divider junction and the base of said second transistor, said PN junction and the base-emitter circuit of said second transistor being forward biased to turn on said second transistor and turn off said output transistor switching means when the voltage at said junction of said voltage divider reaches a predetermined value which is indicative of an output voltage condition of said generator which exceeds said desired regulated value, at least one of said impedances of said voltage divider including a temperature dependent resistance, the impedance connected across said PN junction and the base-emitter circuit of said second transistor having a substantially lower resistance value than the other impedance whereby the voltage at the junction of said voltage divider is reduced in magnitude compared to the voltage at one of said field energizing terminals to prevent false triggering of said circuit including said forward biased PN junction and the base-emitter circuit of said second transistor by transient voltages.

Claim 10

An electrical system comprising, an alternating current generator having an output winding and a field winding, a power bridge rectifier having direct current output terminals connected with said generator, a plurality of auxiliary diodes connected with said output winding, said auxiliary diodes being connected with a third direct current output terminal, said third direct current output terminal and one direct current output terminal of said power bridge rectifier forming field energizing terminals, a voltage regulator including a transistor power output switching means and a transistor input switching means, said output transistor switching means including at least one transistor, said input transistor switching means comprising first and second transistors having a common collector connection with emitter of said first transistor connected to the base of the second transistor, means connecting the collector of said second transistor with the base of said output transistor switching means, means connecting said field winding of said generator and said output transistor switching means in series across said field energizing terminals, means connected with said direct current output terminals of said bridge rectifier and with the base of said first transistor for causing said output transistor switching means to control the field current for said generator as a function of the output voltage of said generator, said last named means operative to maintain the output voltage of said power bridge rectifier at a predetermined desired regulated value, a voltage divider connected across said field energizing terminals including first and second impedances having a common junction, and a semiconductor having a PN junction connected between said voltage divider junction and the base of said second transistor, said PN junction and the base-emitter circuit of said second transistor being forward biased to turn on said second transistor and turn off said output transistor switching means when the voltage at said junction of said voltage divider reaches a predetermined value which is indicative of an output voltage condition of said generator which exceeds said desired regulated value, at least one of said impedances of said voltage divider including a temperature dependent resistance, the impedance connected across said PN junction and the base-emitter circuit of said second transistor having a substantially lower resistance value than the other impedance whereby the voltage at the junction of said voltage divider is reduced in magnitude compared to the voltage at one of said field energizing terminals to prevent false triggering of said circuit including said forward biased PN junction and the base-emitter circuit of said second transistor by transient voltages.

Claim 11

A voltage regulator for regulating the output voltage of a generator comprising, a field current control means having a control electrode and a pair of current carrying electrodes, an input transistor means including at least one transistor, means connecting said input transistor means with the control electrode of said field current control means, the current carrying electrodes of said field current control means adapted to be connected in series with the field of a generator and with a field energizing circuit connected with the output winding of a generator, said voltage regulator having first and second terminals adapted to be connected with said field energizing circuit, a voltage divider comprised of first and second impedances connected across said first and second terminals, said voltage divider having a junction located between said first and second impedances, a voltage sensing circuit including a voltage reference device connected with the base of said input transistor means for controlling the conduction of said input transistor means as a function of the voltage applied to said voltage sensing circuit, said voltage sensing circuit adapted to be connected with said output winding of a generator to thereby regulate the field current of said generator as a function of the output voltage of said generator, a semiconductor device including a PN junction connected between said voltage divider junction and said second terminal, said PN junction of said semiconductor device connected with said input transistor means and operative by conduction in its forward direction to bias said input transistor means to a conductive condition to thereby turn off said field current control means whenever the voltage appearing between said first and second terminals exceeds a predetermined value which is higher than a desired regulated value to be maintained by said voltage regulator, said first impedance connected between said first terminal and said voltage divider junction having a substantially higher resistance than said second impedance whereby said voltage divider reduces the sensitivity of the circuit including said semiconductor to transient voltages appearing between said first and second terminals, one of said impedances of said voltage divider including temperature dependent variable resistance means which responds to the temperature of said voltage regulator and which provides for conduction of said PN junction in a forward direction at a predetermined voltage across said first and second terminals at varying temperatures of said voltage regulator.

Claim 12

A voltage regulator for regulating the output voltage of a generator comprising, a field current control means having a control electrode and a pair of current carrying electrodes, an input transistor means including at least one transistor, means connecting said input transistor means with the control electrode of said field current control means, the current carrying electrodes of said field current control means adapted to be connected in series with the field of a generator and with a field energizing circuit connected with the output winding of a generator, said voltage regulator having first and second terminals adapted to be connected with said field energizing circuit, a voltage divider comprised of first and second impedances connected across said first and second terminals, said voltage divider having a junction located between said first and second impedances, a voltage sensing circuit including a voltage reference device connected with the base of said input transistor means for controlling the conduction of said input transistor means as a function of the voltage applied to said voltage sensing circuit, said voltage sensing circuit adapted to be connected with said output winding of a generator to thereby regulate the field current of said generator as a function of the output voltage of said generator, a semiconductor device including a PN junction connected between said voltage divider junction and said second terminal, said PN junction of said semiconductor device connected with said input transistor means and operative by conduction in its forward direction to bias said input transistor means to a conductive condition to thereby turn off said field current control means whenever the voltage appearing between said first and second terminals exceeds a predetermined value which is higher than a desired regulated value to be maintained by said voltage regulator, said first impedance connected between said first terminal and said voltage divider junction having a substantially higher resistance than said second impedance whereby said voltage divider reduces the sensitivity of the circuit including said semiconductor to transient voltages appearing between said first and second terminals, one of said impedances of said voltage divider including temperature dependent variable resistance means which responds to the temperature of said voltage regulator and which provides for conduction of said PN junction in a forward direction at a predetermined voltage across said first and second terminals at varying temperatures of said voltage regulator.

Claim 13

The voltage regulator according to claim 8 where the semiconductor device is an NPN transistor having an emitter connected to the base of said input transistor means, a collector connected to the collector of said input transistor means and a base connected to said voltage divider junction.

Claim 14

The voltage regulator according to claim 8 where said semiconductor device comprises an NPN transistor having a base connected with said junction on said voltage divider, a collector connected to the collector of said input transistor means and an emitter connected to the emitter of said input transistor means.

Claim 15

An electrical system comprising, an alternating current generator having an output winding and a field winding, a full-wave power rectifier having direct current output terminals and AC input terminals connected to said output winding, a plurality of auxiliary diodes connected with said output winding and with a first field energizing terminal, one of said direct current output terminals of said power rectifier forming a second field energizing terminal, a transistor voltage regulator includIng a transistor output means and transistor input means, said transistor output means including at least one transistor, said transistor input means comprising first and second transistors having a common collector connection with the emitter of said first transistor connected to the base of said second transistor, means connecting the collector and emitter of said output transistor means in series with said field winding and across said field energizing terminals, means connecting the collector and emitter of said second transistor across the vase and emitter of said output transistor means, a voltage sensing circuit coupled to the base of said first transistor and including a Zener diode, means connecting said voltage sensing circuit with the output terminals of said power bridge rectifier whereby it responds to the direct output voltage of said power rectifier, a voltage divider comprised of first and second impedances connected in series across said field energizing terminals, and a semiconductor device comprising a third transistor having its base-emitter circuit connected between said voltage divider junction and the base of said second transistor, said second impedance connected across the base-emitter circuits of said third transistor and said second transistor, the collector of said third transistor connected with the collector of said second transistor, said first impedance having a substantially higher resistance than said second impedance whereby a reduced amplitude voltage appears at said voltage divider junction as compared to the voltage of one of said field energizing terminals, one of said impedances including a temperature sensitive variable resistance which responds to the temperature of said voltage regulator.

Claim 16

An electrical system comprising, an alternating current generator having an output winding and a field winding, a full-wave power rectifier having direct current output terminals and AC input terminals connected to said output winding, a plurality of auxiliary diodes connected with said output winding and with a first field energizing terminal, one of said direct current output terminals of said power rectifier forming a second field energizing terminal, a transistor voltage regulator includIng a transistor output means and transistor input means, said transistor output means including at least one transistor, said transistor input means comprising first and second transistors having a common collector connection with the emitter of said first transistor connected to the base of said second transistor, means connecting the collector and emitter of said output transistor means in series with said field winding and across said field energizing terminals, means connecting the collector and emitter of said second transistor across the vase and emitter of said output transistor means, a voltage sensing circuit coupled to the base of said first transistor and including a Zener diode, means connecting said voltage sensing circuit with the output terminals of said power bridge rectifier whereby it responds to the direct output voltage of said power rectifier, a voltage divider comprised of first and second impedances connected in series across said field energizing terminals, and a semiconductor device comprising a third transistor having its base-emitter circuit connected between said voltage divider junction and the base of said second transistor, said second impedance connected across the base-emitter circuits of said third transistor and said second transistor, the collector of said third transistor connected with the collector of said second transistor, said first impedance having a substantially higher resistance than said second impedance whereby a reduced amplitude voltage appears at said voltage divider junction as compared to the voltage of one of said field energizing terminals, one of said impedances including a temperature sensitive variable resistance which responds to the temperature of said voltage regulator.

Claim 17

An electrical system comprising, an alternating current generator having a polyphase output winding and a field winding, a polyphase bridge rectifier connected with said output winding having direct current output terminals, said direct current output terminals being adapted to feed an electrical load, a plurality of auxiliary diodes connected with said output winding and a first field energizing terminal, one of said direct current output terminals of said power rectifier providing a second field energizing terminal, a transistor voltage regulator including a transistor output means and a transistor input means, said transistor output means including at least one transistor, said transistor input means comprising first and second transistors having a common collector connection with the emitter of said first transistor coupled to the base of said second transistor, means connecting the collector of said second transistor with the base of said output transistor means, a voltage sensing circuit for said voltage regulator connected with said direct current output terminals of said power rectifier, a Zener diode connected with the base of said first transistor and with said voltage sensing circuit for controlling the conduction of said output transistor means of said voltage regulator as a function of the output voltage developed by said generator, a voltage divider comprised of first and second impedances having a common junction connected across said field energizing terminals, and a voltage protecting control transistor having a base connected to said junction on said voltage divider and a collector connected to the collector of said second transistor, the emitter of said second transistor connected with the emitter of said control transistor, said second impedance connnected across the base-emitter circuit of said control transistor, said first impedance having a substantially higher resistance than said second impedance whereby the voltage at said junction is reduced in magnitude to provide a system wherein said voltage protecting control transistor has reduced sensitivity to transient voltages, one of said impedances including a temperature dependent resistance which responds to the temperature of said voltage regulator.

Claim 18

An electrical system comprising, an alternating current generator having a polyphase output winding and a field winding, a polyphase bridge rectifier connected with said output winding having direct current output terminals, said direct current output terminals being adapted to feed an electrical load, a plurality of auxiliary diodes connected with said output winding and a first field energizing terminal, one of said direct current output terminals of said power rectifier providing a second field energizing terminal, a transistor voltage regulator including a transistor output means and a transistor input means, said transistor output means including at least one transistor, said transistor input means comprising first and second transistors having a common collector connection with the emitter of said first transistor coupled to the base of said second transistor, means connecting the collector of said second transistor with the base of said output transistor means, a voltage sensing circuit for said voltage regulator connected with said direct current output terminals of said power rectifier, a Zener diode connected with the base of said first transistor and with said voltage sensing circuit for controlling the conduction of said output transistor means of said voltage regulator as a function of the output voltage developed by said generator, a voltage divider comprised of first and second impedances having a common junction connected across said field energizing terminals, and a voltage protecting control transistor having a base connected to said junction on said voltage divider and a collector connected to the collector of said second transistor, the emitter of said second transistor connected with the emitter of said control transistor, said second impedance connnected across the base-emitter circuit of said control transistor, said first impedance having a substantially higher resistance than said second impedance whereby the voltage at said junction is reduced in magnitude to provide a system wherein said voltage protecting control transistor has reduced sensitivity to transient voltages, one of said impedances including a temperature dependent resistance which responds to the temperature of said voltage regulator.