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US 4,574,222 AGranted
Ballast circuit for multiple parallel negative impedance loads
AssigneeGeneral Electric Company
InventorThomas E. Anderson
Life of this patent
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Abstract
A current-balancing transformer is provided to supply plural parallel-connected electrical loads, especially loads such as gas discharge lamps which exhibit negative impedance and/or non-linear impedance over at least a part of their normal operating range. The current-balancing transformer forces current sharing among the loads so that each of the parallel-connected loads is supplied operating current.
Claims12
A gas discharge lamp circuit comprising:
- power supply means for supplying an a.c. voltage output;
- impedance means for limiting the current level of said a.c. voltage output from said power supply means;
- a plurality of at least three electrical load means connected electrically in parallel for receiving electrical power from said power supply means;
- and
- current-balancing transformer means for providing current sharing among said plurality of electrical load means comprising:
- magnetic core means having a plurality of magnetic core legs equal to the number of electrical load means and magnetic core top bars and bottom bars connecting said plurality of core legs;
- a plurality of electrical windings each disposed upon a respective one of said core legs and connected electrically in series with a respective one of said electrical loads;
- said windings being wound upon said respective core legs such that magnetic flux induced in each of said respective core legs by current flowing through said respective windings to supply said respective loads tends to flow in the same direction relative to said top and bottom bars.
5 more elements
Dependencies are inferred from the claim text.