Controlled dimmer lighting system

#This invention relates to light dimming systems, and more particularly to apparatus for controlling the intensity of electric lamps for illumination control on television and theatrical stages or in similar applications where accuracy as well as specialized control are required to effect predetermined lighting cues.

#To achieve the precise control of illumination required for television studio and stage lighting often requires as many as 400 separate lamps, and it may be desirable to vary the intensity of selected lamps or banks of lamps while leaving the intensity of other lamps or banks of lamps unchanged. Typical lighting control systems in current use utilize a multiplicity of power outlets arranged in a grid on a supporting structure above the stage or studio, with each of the multiplicity of lamps connected to a respective outlet. Alternating current power for the lamps is supplied to the outlet from a central power source, and control of the intensity of the individual lamps is achieved with a plurality of dimmers housed in a large assembly of dimmer racks and may include 40 to 60 or more dimmers of 6KW to 12KW each. Multiple conductors, one from each of the dimmers, are connected to a power patch selector panel from which power-carrying conductors are wired to the grid outlets. By preselected "patching" of the conductors from the dimmers and the conductors to the grid outlets, a given dimmer is operative to control the intensity of a given lamp or group of lamps. The dimmers are controlled from a lighting control console which houses control signal generating equipment, one for each of the dimmers. Such systems are complex, cumbersome (in that a large room is normally required to house the racks of dimmers), and expensive. For example, all currently available SCR dimmers suitable for stage use, regardless of their capacity, contain all of the elements necessary to provide control from the console, one of the more expensive components of which is the control circuit. Consequently, the initial cost of each individual dimmer is high and does not decrease proportionally with a decrease in dimmer capacity; that is, the cost of a 2KW dimmer, for example, is not significantly lower than the cost of a 12KW dimmer.

#It is an object of the present invention to provide a more compact, less expensive, and more convenient dimming control system than heretofore available for controlling intensity levels of a multiplicity of lamps to fulfill the needs of television and theatre.

#A better understanding of the construction and operation of the invention will be had from the following description taken in conjunction with the accompanying drawings, in which:

#FIG. 1 is a block diagram of a typical prior art controlled dimmer lighting system;

#FIG. 2 is a block diagram of a controlled dimmer lighting system embodying the present invention; and

#FIG. 1 is a block diagram of a typical studio lighting system in current use consisting of a multiplicity of power outlets, usually supported on an overhead structure above the studio or theatre stage and arranged in a grid pattern for convenience in plugging in a comparable multiplicity of luminaires, which may be of differing wattages. For illustrative purposes, four outlets are shown at 10, 12, 14 and 16, to which four luminaires 18, 20, 22 and 24 are respectively connected. Depending on the specific lighting function of the luminaires, they may be of the same or different wattage, and it will be understood that they represent but a few of a larger number of separate lamps found in typical systems, sometimes numbering as many as 400.

#Alternating current power for the lamps, normally at 60 Hz and 120 volts, is supplied by a power source 26 which includes power switch gear and circuit breakers. The source 26 supplies power to a multiplicity of dimmers, which are usually of the solid state SCR-type and mounted in a large assembly of dimmer racks 28 and placed in a separate dimmer rack room. A typical installation may include 40 to 60 or more dimmers of 6KW to 12KW each. Each of the dimmers is connected to a power patch selector panel 30 for assigning grid outlets for each luminaire to a dimmer as required for illumination of a given scene. It will be appreciated that cables having high current-carrying capacity are required for cabling the power source to the dimmer racks, from the dimmers to the patch selector, and from the patch selector to the grid outlets. Each of the dimmers is controlled by its own dimmer control circuit, all of which are contained in an operator lighting control console 32, enabling the operator to control the intensity of given ones or groups of the luminaires as determined by the assignment of outlets to a dimmer and the lighting cues for the particular program.

#The control dimmer lighting system according to the present invention, shown in block diagram in FIG. 2, includes the conventional grid of power outlets, only four of which are shown at 36, 38, 40 and 42, it being understood that a much greater number are found in the usual lighting system. The outlets are energized from a power source 44, which includes the usual main circuit breakers for the system, through load circuit breaker panels 46. Only a single cable pair is required to couple the power source 44 to the load circuit breaker panels, and since the invention contemplates the control in unison of a plurality of lamps included in preselected groups, a number of cables corresponding to the number of preselected groups are connected from the load circuit breaker panel 46 to their respective grid outlets. The diagram of FIG. 2 illustrates a group consisting of four outlets all of which are energized by a common cable 48 connected to its associated circuit breaker in the load circuit breaker panel 46.