Fused lead wire for ballast protection
AssigneeUniversal Lighting Technologies, Inc.
InventorsRobert V. Burke, Michael Litvinovich
Life of this patent
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Abstract
A ballast having fused leads protects against uncommon, but harmful, ballast failures. The fused leads prevent a current in the primary coil of the ballast from exceeding a potentially damaging value. A thermal protector shorts the primary ballast coil if the temperature of the secondary ballast coil exceeds a potentially damaging value. Since the thermal protector permanently disables the ballast, potentially damaging repetitive overheating of the ballast is prevented.
Claims1
A method of preventing non-passive ballast failure caused by overheating in a high-intensity discharge lamp ballast having a primary coil magnetically coupled to a secondary coil, the method comprising:
- detecting a temperature directly from the secondary coil of the ballast;
- comparing the detected secondary coil temperature to a predetermined temperature threshold;
- detecting a current through the primary coil of the ballast;
- comparing the detected current through the primary coil to a predetermined current threshold;
- permanently disabling the ballast in response to one or more of
- a first ballast disabling condition associated with a detected secondary coil temperature in excess of the predetermined temperature threshold and
- a second ballast disabling condition associated with a detected current through the primary coil in excess of the predetermined current threshold;
- wherein the step of permanently disabling the ballast further comprises disabling one or more ballast leads having an integral fuse coupled between a power source and the primary coil of the ballast;
- and
- wherein the step of permanently disabling the ballast in response to the first ballast disabling condition further comprises triggering a thermal protector with normally open contacts electrically coupled to the primary coil, wherein a portion of the primary coil is shorted by connecting of the normally open contacts.
Dependencies are inferred from the claim text.