Power reduction control for inductive lighting installation
First Claim
1. A control system for continuously, selectively reducing power consumption in an inductive lighting installation energized from an A.C. power source, the installation including at least one ga discharge lamp such as a fluorescent lamp energized through any of a plurality of different types of electromagnetic ballast having different harmonic distortion characteristics, the control system comprising:
- load energizing circuit means, including a signal-actuated normally-closed primary switch, for connecting an A.C. power source to the lighting installation;
a signal-actuated, normally-open secondary switch connected in parallel with the lighting installation;
actuation means for generating actuation signals and applying such actuation signals to the primary and secondary switches to actuate the primary switch open and to actuate the secondary switch closed in approximate time coincidence in each half-cycle of the A.C. power;
zero-crossing detector means for generating zero-crossing signals at times TX indicative of zero-voltage transitions in the A.C. power;
and program means, connected to the zero-crossing detector means and to the actuation means, programming the actuation means to generate(a) power reduction actuation signals at times T1 and T2 in each half-cycle of the A.C. power,(b) a first filter actuation signal at a time T3 prior to each zero-crossing time TX, and(c) a second filter actuation signal at a time T4 following each zero-crossing time TX;
the program means including a plurality of programs each establishing a set of times T1, T2, T3 and T4 for several different power reduction levels for a particular type of ballast;
and selection means for selecting a program to match the ballast type of the load.
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Accused Products
Abstract
A control system for reducing power used by an inductive lighting installation, usually plural fluorescent lamps and a ballast, includes an A.C. power input circuit to the installation with a signal-actuated, normally-closed primary switch in series in the circuit; a signal-actuated normally-open secondary switch is in shunt with the load. The two switches are actuated substantially simultaneously in each half-cycle of the A.C. power input, once for power reduction for a time interval T1-T2 and once for harmonic distortion reduction for a time T3-T4 that encompasses each A.C. power zero-crossing time TX. The control system has N different timing programs for times T1-T2 and T3-T4, each program corresponding to one type of ballast. In each program times T3 and T4 are constant; only the times T1 and T2 are varied for a series of successively greater power reductions; the maximum power reduction may be as much as 30 to 40 percent. The system is provided with protection circuits to protect against unusual line or load voltage or current conditions.
108 Citations
10 Claims
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1. A control system for continuously, selectively reducing power consumption in an inductive lighting installation energized from an A.C. power source, the installation including at least one ga discharge lamp such as a fluorescent lamp energized through any of a plurality of different types of electromagnetic ballast having different harmonic distortion characteristics, the control system comprising:
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load energizing circuit means, including a signal-actuated normally-closed primary switch, for connecting an A.C. power source to the lighting installation; a signal-actuated, normally-open secondary switch connected in parallel with the lighting installation; actuation means for generating actuation signals and applying such actuation signals to the primary and secondary switches to actuate the primary switch open and to actuate the secondary switch closed in approximate time coincidence in each half-cycle of the A.C. power; zero-crossing detector means for generating zero-crossing signals at times TX indicative of zero-voltage transitions in the A.C. power; and program means, connected to the zero-crossing detector means and to the actuation means, programming the actuation means to generate (a) power reduction actuation signals at times T1 and T2 in each half-cycle of the A.C. power, (b) a first filter actuation signal at a time T3 prior to each zero-crossing time TX, and (c) a second filter actuation signal at a time T4 following each zero-crossing time TX; the program means including a plurality of programs each establishing a set of times T1, T2, T3 and T4 for several different power reduction levels for a particular type of ballast; and selection means for selecting a program to match the ballast type of the load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification