Overvoltage protection circuit

Claim 2

In an electrical generating system for an automotive vehicle the combination comprising, an electrical energy generator having output windings and a control winding, a regulator means connected to said output windings and said control winding for limiting the energization of said control winding and the magnitude of the voltage produced in said output windings, an overvoltage protection circuit means for disconnecting said regulator means and said control winding from said output windings when the voltage produced in said output windings exceeds a predetermined level, said overvoltage protection circuit means comprising, means connected to said output windings for sensing the output voltage of said output windings, a normally closed switch means connecting said output windings with said regulator means, and means coupled to said means for sensing the output voltage of said windings and switch means for opening said switch means when the output voltage of said windings exceeds said predetermined level and for closing said switch means when the output voltage of said windings falls to a second predetermined level substantially below said first predetermined level.

Claim 3

The combination of claim 1 in which an electrical storage battery is connected to said output windings And in which the first predetermined level is greater than the terminal voltage of said electrical storage battery and said second predetermined level is approximately one-half the terminal voltage of said electrical storage battery.

Claim 4

The combination of claim 2 in which said last mentioned means comprises a solid state switching network connected to said output windings and said electrical storage battery and said normally closed switch means comprises a pair of contacts and a winding, said contacts being closed when said winding is energized, said solid state switching network being coupled to said winding for controlling the energization of said winding.

Claim 5

The combination of claim 3 in which said solid state switching network comprises a first and a second solid state switching device, means coupling said first and second solid state switching devices for maintaining said second solid state switching device in a conducting state when said first solid state switching device is in a nonconducting state and for maintaining said second solid state switching device in a nonconducting state when said first solid state switching device is in a conducting state, means coupled to said means for sensing the output voltage of said output windings and said first solid state switching device for maintaining said first solid state switching device in a nonconducting state and said second solid state switching device in a conducting state when the voltage produced in said output windings is below said first predetermined level, for switching said first solid state switching device to a conducting state and said second solid state switching device in a nonconducting state when the voltage produced in said output windings exceeds said first predetermined level, for maintaining said solid state switching devices in such last mentioned state as long as the terminal voltage of said battery is above said second substantially lower predetermined level and for switching said solid state switching devices to said first mentioned state when the terminal voltage falls to the value of said second substantially lower predetermined level.

Claim 6

In an electrical generating system the combination comprising, an electrical energy generator having output windings and a control winding, a regulator connected to said output windings and said control winding for limiting the energization of said control winding and the magnitude of the voltage produced in said output windings, and means coupled to said output windings and said regulator for decoupling said output windings from said regulator when the voltage produced in said output windings exceeds a first predetermined level, for maintaining said output windings decoupled from said regulator when the voltage produced in said output windings is greater than a second substantially lower predetermined level and for recoupling said output windings to said regulator when the voltage produced in said output windings falls to said second substantially lower predetermined level.

Claim 7

In an electrical generating system the combination comprising, an electrical energy generator having output windings and a control winding, a regulator connected to said output windings and said control winding for limiting the energization of said control winding and the magnitude of the voltage produced in said output windings, and means coupled to said output windings and said regulator for decoupling said output windings from said regulator when the voltage produced in said output windings exceeds a first predetermined level, for maintaining said output windings decoupled from said regulator when the voltage produced in said output windings is greater than a second substantially lower predetermined level and for recoupling said output windings to said regulator when the voltage produced in said output windings falls to said second substantially lower predetermined level.

Claim 8

The combination of claim 5 in which an electrical storage battery is connected across said output windings and in which said first predetermined level is greater than the terminal voltage of said battery and said second substantially lower predetermined level is less than the terminal voltage of said battery.

Claim 9

The combination of claim 6 in which said last mentioned means comprises a relay having contacts and a winding, said contacts being positioned between said output windings and said regulator, and solid state switching means connected across said output windings and in circuit with said relay winding for energizing said winding and closing said contacts when the voltage produced in said output windings is between the terminal voltage of said battery and said first predetermined level, for de-energizing said relay winding and opening said contacts when the voltage produced in said output windings exceeds said first predetermined level, for maintaining said relay windiNg de-energized and said relay contacts open when the voltage produced in said output windings is above said substantially lower predetermined level and for closing said relay contacts when the voltage produced in said output windings falls to said substantially lower predetermined level.

Claim 10

The combination of claim 7 in which said solid state switching means comprises a pair of solid state switching devices, each of said solid state switching devices including a pair of output electrodes and a control electrode, the output electrodes of said first solid state switching device being connected across said output windings, means coupled to the control electrode of said first solid state switching device and to said output windings for maintaining said first solid state switching device in a nonconducting state when the voltage produced in said output windings is below said first predetermined level and for switching said first solid state switching device to a conducting state when the voltage produced in said output windings is equal to or above said first predetermined level, the output electrodes of said second solid state switching device being connected in series circuit with said relay winding, said series circuit being connected across said output windings, means coupling the output electrodes of said first solid state switching device to the control electrode of said second solid state switching device for maintaining said second solid state switching device in a conducting state when the voltage produced in said output windings is below said first predetermined level and for switching said second solid state switching device to nonconducting state when said first solid state switching device is in a conducting state and means coupled to said control electrode of said first solid state switching device for maintaining said first solid state switching device in a conducting state when the voltage produced in said output windings is above said second lower predetermined level and for switching said first solid state switching device to a nonconducting state when the voltage produced in said output windings falls to said second lower predetermined level.

Claim 11

The combination of claim 6 in which said last mentioned means comprises a voltage sensing means connected to said output windings and a solid state switching network coupled to said output windings and said voltage sensing means, a relay having contacts coupled between said output windings and said regulator and a winding connected in circuit with and controlled by said solid state switching network.

Claim 12

The combination of claim 9 in which said solid state switching network and said voltage sensing means includes means for energizing said relay winding and thereby closing said contacts upon energization of said solid state switching network from said electrical storage battery and said output windings, said voltage sensing network and said solid state switching network including means for de-energizing said relay winding and opening said contacts when the voltage produced in said output windings exceeds said first predetermined level, for maintaining said relay winding de-energized and said contacts open as long as the voltage produced in said output windings is above said second substantially lower predetermined level and for energizing said relay windings and closing said contacts when the voltage produced in said output windings falls to said second substantially lower predetermined level.