Over-voltage protection circuit for wye connected electric machine
AssigneeC. E. Niehoff & Co.
InventorsHans Jakobs, Charles J. Juhnke
Life of this patent
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Abstract
A load dump circuit for a wye connected electric generating machine includes a silicon controlled rectifier connected between the common terminal of the wye and one of the output terminals of the machine. A Zener diode sensing circuit is connected to the common wye terminal and to the control terminal of the controlled rectifier for rendering the controlled rectifier conductive to shunt the output windings in the event of an excessive voltage being developed thereacross as a result of a rapid load reduction or similar condition. Means are also provided to terminate field excitation during the shunting condition.
Claims16
An electric power generating system comprising:
- a plurality of output windings connected together in wye configuration at a common junction;
- first and second power output terminals;
- means connecting said output windings to said output terminals;
- voltage sensing means responsive to a voltage indicative of an excessive voltage condition between said power output terminals;
- and
- switch means having first and second main terminals and a control terminal, said first main terminal being connected to said common junction, said second main terminal being connected to one of said power output terminals, and said control terminal being coupled to said voltage sensing means, said switch means being responsive to said voltage sensing means for electrically connecting said common junction to said one output terminal when the voltage between said power output terminals exceeds a predetermined amplitude.
An electronic load dump circuit for an electric generating machine having an excitation winding, a pair of output terminals and a plurality of output windings connected together at a common junction in a wye configuration and coupled to said output terminals, said system comprising:
- avalanche means having a conductive and a non-conductive state electrically coupled to one of said output windings, said avalanche means being responsive to the voltage at said one output winding and operable to said conductive state when the voltage exceeds a predetermined amplitude;
- electronic switch means having main terminals connected to said common junction and to one of said output terminals, and a control terminal;
- and
- means connecting said control terminal to said avalanche means, said electronic switch means being responsive to said conductive state for providing a low impedance path between common junction and said one of said output terminals for effectively short circuiting said common junction to said one output terminal.
In an electrical power system having a pair of output terminals and employing a plurality of output windings, said windings being connected together in a wye configuration at a common junction, an over-voltage protection system comprising:
- voltage sensing means electrically coupled to one of said output windings for sensing the voltage thereat;
- and
- switch means coupled between said common junction and one of said output terminals, said switch means being further coupled to said voltage sensing means and responsive thereto for electrically connecting said common junction to said one of said output terminals when the voltage at one of said windings exceeds a predetermined amplitude.
Dependencies are inferred from the claim text.