Alternator regulator having output monitoring and limiting controls

• US 4,839,575 A
• Filed: 08/15/1986
• Issued: 06/13/1989
• Est. Priority Date: 08/15/1986
• Status: Expired due to Term

• Current Assignee: Marathon Electric Manufacturing Corp (Regal Rexnord Corp.)
• Original Assignee: Marathon Electric Manufacturing Corp (Regal Rexnord Corp.)
• Inventors: MacFarlane, Alistair A.
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US06/897,134
• Time in Patent Office: 1,033 Days
• Field of Search: 322/25, 322/27, 322/28, 322/99, 361/20, 361/21, 123/179 A
• US Class Current: 322/25
• CPC Class Codes: H02H 7/06 for dynamo-electric generators; for synchronous capacitors
• CPC Class Codes: H02P 9/10 Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load

Abstract

An alternator regulator includes a status sensor connected to monitoring the connection of a voltage sensor to the alternator and a separate current limited monitor unit to regulate the output in accordance with the alternator current output. The sensor monitor unit includes a continuity circuit detector coupled to the voltage sensor and operable to continuously monitor the state of the connection to the alternator. A fault in the circuit connection such as a loose terminal, a broken lead or other such faults, opens the continuity circuit and generates a signal which drive the regulator off and terminates operation of the alternator, thereby protecting the alternator from possible destruction. A voltage/current mode selector receives a voltage related signal and a current related signal. A signal comparator is coupled to the voltage related signal and the sensed current related signal and generates a logic control signal applied to the selector to transmit one of the two signals. If the voltage drops, the current control is automatically triggered at a selective level to control the alternator output in accordance with the current output. The current limit control will limit the alternator output when zero voltage is occasioned by a short circuit condition. The conjoint control effected by the separate status sensing monitor positively shuts down the alternator, preventing operation of the current mode and insuring total protection of the alternator system.

Claims

1. A voltage regulator for controlling an alternator establishing an electrical output including an output voltage and an output current to a connected load, comprising

a control circuit means having output means controlling the electrical output of such alternator,

a current sensing means having connection means adapted to be connected to the output of the alternator and establishing a current-related signal proportional to the level of the output current from the alternator, a voltage sensing means having an input means and connection means adapted to connect said input means to the output of the alternator and establishing a voltage-related signal proportional to the level of the voltage output of the alternator, a voltage/current selection means having a first input connected to said current sensing means and a second input connected to said voltage sensing means and having an output means for controlling transmission of signals from said sensing means for controlling said alternator, said selection means transmitting a single one of said signals from said sensing means,

a sensor continuity detector connected to the connection of said voltage sensing means to said alternator and operable to separately detect the lack of continuity in the connection means of the voltage sensor means to said alternator and to thereby detect an essentially open circuit condition in said connection means, and

means connecting said sensor continuity detector to said control circuit means to control said alternator and override the signal from said selection means.

2. The voltage regulator of claim 1, wherein said selection means includes a comparator means having first and second inputs connected respectively to said current level sensing means and said voltage sensing means and having an output connected to actuate said selection means in accordance with the relative input signals at said first and second inputs.

3. The voltage regulator of claim 1, wherein said sensor continuity detector is operable to shutdown said alternator.

4. The voltage regulator of claim 1, wherein said control circuit means includes

alternator excitation level control means having exciter input means and controlling the excitation of the alternator in accordance with the signal level at said exciter input means, said input means adapted to receive a variable level control signal from said selection means to vary the excitation in accordance with the voltage signal to establish and maintain a selected output voltage and in accordance with the current signal if said current level rises above a selected level relative to said voltage signal.

5. The voltage regulator of claim 4, wherein said selection means includes a comparator unit connected to said current sensing means and connected to said voltage sensing means to receive the corresponding control signals from said sensing means and operable to provide a first control signal demanding a voltage control and a second control signal demanding a current control related to the relative levels of the outputs of said sensing means.

6. The voltage regulator of claim 1, wherein said continuity detector includes a D.C. current supply connected to establish a D.C. current through said alternator and said input means, said continuity detector being connected to the input means and establishing a control signal in response to a change in said D.C. current level, and means connecting said detector to limit operation of the alternator in response to a selected change in said D.C. current flow.

7. The regulator of claim 6, wherein said D.C. current supply is a permanent magnet generator and a full wave bridge rectifier connected to the output of said generator to establish said D.C. current supply, said continuity detector including means connected to said rectifier to establish a D.C. current flow through said alternator and sensor means, and means to monitor the level of said D.C. flow and thereby the continuity of the connecting of the voltage sensing means to the alternator.

8. The regulator of claim 6, wherein said regulator is adapted to control a polyphase alternator, said continuity circuit detector includes having separate phase connection means for separately sensing the D.C. current in each phase connection to the alternator and establishing corresponding phase signals and means for combining said phase signals to form said control signal whereby said control signal changes in response to a change in any phase connection.

9. The regulator unit of claim 8, wherein a plurality of resistor means connect said D.C. current supply to said sensor continuity detector for establishing said D.C. current through said input means and said alternator, and having a voltage level sensing means having input means connected to said resistor means for detecting the level of said D.C. current.

10. The regulator unit of claim 8, wherein said continuity detector includes an integrating operational amplifier having a first input means and a second input means, a voltage dividing network including summing means to combine the phase currents and establishing a voltage signal proportional to the summated D.C. phase currents, and a reference level voltage means connected to said second input means.

11. A regulator for controlling an alternator,

a control means having an output means for controlling the excitation of the alternator and thereby the electrical output of the alternator,

a current sensing means having input means for connection to the output of the alternator and establishing a current-related signal proportional to the voltage output of the alternator,

a voltage sensing means having input means for connection to the output of the alternator and establishing a voltage-related signal proportional to the voltage output of the alternator,

a voltage/current selector means having input means connected to said current sensing means and to said voltage sensing means and having an output means and selectively connecting said output means to said current sensing means or said voltage sensing means, and signal level comparator means having input means connected to said current sensing means and to said voltage sensing means and having an output means connected to actuate said selector means in accordance with the level of the signals from said sensing means, said comparator means connecting said voltage sensing means to said output means and responsive to a voltage-related signal with said alternator producing a zero output to connect said current sensing means to said output means to limit the current and prevent a damaging current flow from said alternator.

12. The regulator of claim 11, wherein said comparator means compares the level of the signals from said sensing means and sets said selector means to transmit said voltage signal with said voltage signal above a selected level.

13. The regulator of claim 11, having a connection circuit means connecting said input means of said voltage sensing means to said alternator, and a sensor continuity detector operable to directly detect the continuity of said connection circuit means and an essentially open circuit condition at said input means of said voltage sensing means, and means connected to said input means connected to said selection means and to said sensor continuity detector and operable in response to a selected signal from said sensor continuity detector to essentially shut down said alternator.

14. The regulator of claim 11 for a polyphase alternator wherein said current sensing means includes a plurality of current signal branches, one for each phase and having a current input, each branch including a rectifying means and a peak detector producing an output corresponding to the amplitude of the branch, a smoothing circuit connected to said peak detectors to establish a variable D.C. voltage signal proportional to the peak current.

15. The regulator of claim 14, including an amplifier connected to said smoothing circuit and a clamp means connected to limit the input signal to said amplifier.

16. The regulator of claim 11, wherein said comparator unit includes a difference amplifier having first and second inputs connected to said sensing means, a triggered logic circuit connected to said difference amplifier to produce alternate logic output signals in accordance with the level of the signals from the sensing means.

17. The regulator of claim 16, wherein said comparator means includes is an integrated circuit switch having said control input connected to said triggered logic circuit.

18. A voltage regulator unit for regulating an alternator,

an output sensor means having an input means connected to the output of the alternator to sense the electrical output of the alternator and having processing means, conductors connecting said processing means and said input means to establish a related output signal, control means connected to said processing means, and operable to control the output of the alternator, a sensor continuity detector connected to the output sensor means and directly monitoring the physical continuity of the conductors between said input means and said processing means and establishing a control signal in response to an opening in said conductors from the input means to the output sensor means, limit means connecting said detector to said control means to signal said opening and thereby connection loss in said conductors, said regulator including a D.C. power supply, said detector including means connected to said power supply to establish a D.C. current flow through said alternator and said input means to said sensing means, and said detector monitors the level of the D.C. current flow and thereby the continuity of the coupling of the sensor input means to the alternator.

20. The regulator unit of claim 18, wherein said monitor means includes an integrating operational amplifier having a first input means and a second input means, a voltage dividing network including summing means to combine the phase currents and establishing a voltage signal proportional to the summated D.C. phase currents, and reference voltage means connected to said second input means.

21. The regulator unit of claim 18 having a logic D.C. voltage means, said detection means including resistor means connected said D.C. voltage means to said sensor means for establishing a D.C. current through said input means and the alternator, a voltage sensing means having input means connected to resistor means for detecting the presence of said D.C. current.

19. In combination, a generator unit and a voltage regulator for controlling an alternator establishing electrical output including an output voltage and an output current to a connected to a load, said regulator comprising

a control circuit means having output means controlling the electrical output of such alternator,

a current sensing means having input means adapted to be connected to the output of the alternator and establishing a current-related signal proportional to the level of the output current from the alternator, a voltage sensing means having an input means adapted to be coupled to the output of the alternator and establishing a voltage-related signal proportional to the level of the voltage output of the alternator, a voltage/current selection means having a first input connected to said current sensing means and a second input connected to said voltage sensing means and having an output means for controlling transmission of signals from said sensing means for controlling said alternator, said selection means transmitting a single one of said signals from said sensing means,

a sensor continuity detector for connection to the input means of said voltage sensing means to said alternator and for separately detecting the lack of continuity in the connection means of the voltage sensor means to said alternator and to thereby detect an essentially open circuit condition in said connection means,

means connecting said sensor continuity detector to said control circuit means to control said alternator and override the signal from said selection means, and said generator unit including a permanent magnet generator, a rectifier means connected to the output of said generator and establishing a D.C. power supply to said voltage regulator, said detector including means connected to said rectifier means to establish a D.C. current flow through said alternator and the input means to said voltage sensing means, and said detector includes a D.C. current sensing means monitoring the level of said D.C. current flow and thereby the continuity of the connection of the voltage sensing means to the alternator.