Self-contained, self-snubbed, HID dimming module that exhibits non-zero crossing detection switching
AssigneeHubbell Incorporated
InventorsChristopher Hudson, Thomas Hirt
Life of this patent
Estimating the term…
Abstract
A protection circuit for an HID dimming circuit is provided. A resistive component limits the initial current after a relay closes and current flows from a charged capacitor to a second capacitor. An inductive component limits the rate of change of current through the circuit. A voltage limited device limits voltage across the contacts of a solid state relay. The circuit is preferably formed in a small module that is adapted to be plugged into an HID lighting device.
Claims32
A protective circuit for an HID dimming device comprising:
- a relay having two contacts, a resistive device and an inductive device connected in series between a first capacitive device and a second capacitive device, said resistive device adapted to limit an initial current between said capacitive devices when said relay is closed, said inductive device adapted to limit the rate at which said current between said capacitive devices changes;
- and
- a voltage limiting device connected between said relay contacts and adapted to prevent a voltage across said relay contacts from exceeding a predetermined threshold.
A method of protecting an HID dimming device comprising the steps of:
- preventing an initial current between at least two capacitors that are adapted to be connected when a relay closes from exceeding a predetermined limit;
- limiting the rate of change of current between the two capacitors to below a predetermined frequency;
- and
- limiting the voltage across two contacts of the relay to below a rated voltage.
A dimming module comprising:
- a relay having two input control contacts and two output contacts adapted to be connected to first and second capacitors;
- a protection circuit comprising a resistive device adapted to limit an initial current between said capacitive devices when said relay is closed, an inductive device adapted to limit the rate of change of current between said capacitive devices, and a voltage limiting device connected between the relay contacts and adapted to prevent a voltage across said relay contacts from exceeding a predetermined threshold.
An HID dimming module comprising:
- a non-conductive housing containing a dimming control drive for an HID lamp and a snubber circuit;
- terminals extending from said housing adapted to connect said dimming module to a relay socket of a HID lighting device;
- wherein said snubber circuit comprises a relay having two contacts, a resistive device and an inductive device connected in series between a first capacitive device and a second capacitive device, said resistive device adapted to limit an initial current between said capacitive devices when said relay is closed, said inductive device adapted to limit the rate at which said current between said capacitive devices changes;
- and a voltage limiting device connected between said relay contacts and adapted to prevent a voltage across said relay contacts from exceeding a predetermined threshold.
Dependencies are inferred from the claim text.