Abstract: A shutter section includes a stack of circular plates independently rotatable in a nest formed as a laminar formation of rings. The plates have central openings defining a light path. Four central plates in the stack are shutter guide plates with radial guide slots slideably holding shutter blades. Two outer pairs of plates are shutter drive plates connected by cams to the shutter blades. Simultaneous rotation of a shutter guide plate and associated shutter drive plate causes rotation of an associated shutter blade around the light path. Rotation of a shutter drive plate while the associated shutter guide plate is stationary causes the cam to move the associated shutter blade radially. The nest is enclosed by end plates. A motor section has motors driving pinions to rotate the circular plates. The circular plates, rings pinions and shutter blades are made of sheet metal.

Abstract: Current sensing resistors are connected directly to output terminals of MOSFETs forming the series switching stage of a PWM sinewave dimmer. An analog sensed current signal is coupled through an EMI resistant current link to comparators that provide an overcurrent indication in response to an overcurrent condition. A logic circuit overrides PWM control signals from a programmable controller, and operates drivers to render the series switching stage nonconductive and to render a clamp switching stage conductive until after the end of the current PWM duty cycle power on segment. The logic circuit sends an overcurrent signal through an optocoupler to an input of the programmable controller. The input of the controller is polled at a clock frequency for overcurrent signals and if the count exceeds a limit in any half cycle, or a maximum sum in sixteen half cycles of the AC supply, the series switching stage is rendered nonconductive and the clamp switching stage is rendered conductive pending a reset signal.

Abstract: A theatrical luminaire for entertainment and architectural applications includes a lamp socket accessible from the exterior of the luminaire housing. A lamp includes a base, a bulb on one side of the base and a handle on the other side. The handle is grasped to insert the lamp into the socket. When the base is mounted in the socket, the bulb extends through the socket into the luminaire and the handle remains accessible at the exterior of the luminaire. The lamp is mounted with a one-handed push and turn motion, and contacts on wings of the base engage socket contacts as the lamp is turned to its final position. The socket is mounted on a support that is adjustable relative to the luminaire housing to preserve the correct lamp positioning when the lamp is replaced.

Abstract: A driver circuit is provided for a stepper motor which utilizes a processor that outputs a PWM signal. The driver circuit includes an H-bridge circuit having first and second inputs, and a switching circuit having an input and an output. The first H-bridge input and the switching input connect to the PWM signal output from the processor, and the switching output connects to the second H-bridge input. The switching circuit performs an inversion of a duty cycle of the PWM signal when the PWM signal is present, and a non-inversion of the duty cycle when the PWM signal is not present.

Abstract: A cassette containing a gel scroll is releasably attached to the forward portion of a housing of a luminaire. A light path through the cassette is aligned with a light exit opening of the luminaire. A gel scroll is wound upon a pair of drums in the cassette and intersects the light path. The drive motor for the cassette is contained in the housing of the luminaire. A drive system for the drums includes a driven member in the cassette that engages a drive member of the luminaire driven by the motor when the cassette is mounted on the luminaire. A fan in the luminaire moves cooling air through the cassette when the cassette is mounted on the luminaire.

Abstract: A zoom lens system includes a motor driven lens assembly that is movable on a track in a normal movement range for adjusting the light beam range angle of a luminaire. A pair or doors are pivoted to opposite sides of the frame of the lens assembly and are normally biased to an inactive position where the doors are parallel to and outside of the light path in the luminaire. The doors hold optical media such as diffuser gels. The lens assembly can be moved beyond the normal movement range to an actuation position where projections on the doors engage actuation abutments adjacent the track to move the doors to an active position overlying the lens with the optical media in the light path. A latch holds the door in the active position. The lens assembly can be moved beyond the actuation position to a deactivation position where a deactivation abutment releases the latch freeing the doors to return to the inactive positions.

Abstract: A shutter section includes a stack of circular plates independently rotatable in a nest formed as a laminar formation of rings. The plates have central openings defining a light path. Four central plates in the stack are shutter guide plates with radial guide slots slideably holding shutter blades. Two outer pairs of plates are shutter drive plates connected by cams to the shutter blades. Simultaneous rotation of a shutter guide plate and associated shutter drive plate causes rotation of an associated shutter blade around the light path. Rotation of a shutter drive plate while the associated shutter guide plate is stationary causes the cam to move the associated shutter blade radially. The nest is enclosed by end plates. A motor section has motors driving pinions to rotate the circular plates. The circular plates, rings pinions and shutter blades are made of sheet metal.

Abstract: A shutter section includes a stack of circular plates independently rotatable in a nest formed as a laminar formation of rings. The plates have central openings defining a light path. Four central plates in the stack are shutter guide plates with radial guide slots slideably holding shutter blades. Two outer pairs of plates are shutter drive plates connected by cams to the shutter blades. Simultaneous rotation of a shutter guide plate and associated shutter drive plate causes rotation of an associated shutter blade around the light path. Rotation of a shutter drive plate while the associated shutter guide plate is stationary causes the cam to move the associated shutter blade radially. The nest is enclosed by end plates. A motor section has motors driving pinions to rotate the circular plates. The circular plates, rings pinions and shutter blades are made of sheet metal. Shutters may be provided as interleaved pairs each driven by a pair of rotatable drive plates.

Abstract: A heat sink with fins has a flat, planar surface soldered to a metallic layer at one surface of a flat, planar ceramic layer. The opposite surface of the ceramic layer has a metallic pattern including base areas for high power, high frequency load switching MOSFETs. Lead frames are soldered between the lead frame base areas and base contact areas of the MOSFET packages. Thermal conduction between the MOSFETs and the heat sink dissipates the heat from switching losses. A gate drive circuit board for the load switching system is supported spaced from the and is separated from the MOSFETs by a thermally blocking air gap, with the component side of the gate drive circuit board facing away from the MOSFETs. Spade terminals of the lead frames extend through openings in the gate drive circuit board to route high power signals independently of the gate driver circuit board.

Abstract: A cassette containing a gel scroll is releasably attached to the forward portion of a housing of a luminaire. A light path through the cassette is aligned with a light exit opening of the luminaire. A gel scroll is wound upon a pair of drums in the cassette and intersects the light path. The drive motor for the cassette is contained in the housing of the luminaire. A drive system for the drums includes a driven member in the cassette that engages a drive member of the luminaire driven by the motor when the cassette is mounted on the luminaire. A fan in the luminaire moves cooling air through the cassette when the cassette is mounted on the luminaire.

Abstract: A heat sink with fins has a flat, planar surface soldered to a metallic layer at one surface of a flat, planar ceramic layer. The opposite surface of the ceramic layer has a metallic pattern including base areas for high power, high frequency load switching MOSFETs. Lead frames are soldered between the lead frame base areas and base contact areas of the MOSFET packages. Thermal conduction between the MOSFETs and the heat sink dissipates the heat from switching losses. A gate drive circuit board for the load switching system is supported spaced from the and is separated from the MOSFETs by a thermally blocking air gap, with the component side of the gate drive circuit board facing away from the MOSFETs. Spade terminals of the lead frames extend through openings in the gate drive circuit board to route high power signals independently of the gate driver circuit board.

Abstract: A theatrical luminaire for entertainment and architectural applications includes a lamp socket accessible from the exterior of the luminaire housing. A lamp includes a base, a bulb on one side of the base and a handle on the other side. The handle is grasped to insert the lamp into the socket. When the base is mounted in the socket, the bulb extends through the socket into the luminaire and the handle remains accessible at the exterior of the luminaire. The lamp is mounted with a one-handed push and turn motion, and contacts on wings of the base engage socket contacts as the lamp is turned to its final position. The socket is mounted on a support that is adjustable relative to the luminaire housing to preserve the correct lamp positioning when the lamp is replaced.

Abstract: A self contained multiple dimming channel package includes a housing with a main power circuit board supported on its bottom wall and a control circuit board extending laterally and vertically to baffle air flow through the housing. A cross flow cooling fan forces air through an opening in the control board and across power switching modules and toroidal chokes mounted to the main board. Each power switching module includes a heat sink with fins parallel to the air flow, and the chokes are mounted in rows with their central openings aligned with the air flow. The power switching modules include circuits attached to the heat sinks with terminals releasably plugged into mating connectors on the main board. Circuit breaker switches are snapped into place in the housing. The front corners of the housing are provided with integral mounting bracket and handle members.

Abstract: A self contained multiple dimming channel package includes a housing with a main power circuit board supported on its bottom wall and a control circuit board extending laterally and vertically to baffle air flow through the housing. A cross flow cooling fan forces air through an opening in the control board and across power switching modules and toroidal chokes mounted to the main board. Each power switching module includes a heat sink with fins parallel to the air flow, and the chokes are mounted in rows with their central openings aligned with the air flow. The power switching modules include circuits attached to the heat sinks with terminals releasably plugged into mating connectors on the main board. Circuit breaker switches are snapped into place in the housing. The front corners of the housing are provided with integral mounting bracket and handle members.

Abstract: Power for one or more luminaire accessories is extracted from a series of lamp operating pulses provided by a phase angle dimmer. A DC power supply is connected to the output of the dimmer to develop and store DC accessory power. A lamp controller is connected to the output of the dimmer to transfer power from the lamp operating pulses to the lamp. The lamp controller has a variable pulse transfer characteristic for providing lamp power without lamp performance degradation caused by accessory power variations. The variable pulse transfer characteristic can be implemented by a switching device that interrupts or blocks selected portions of the lamp operating pulses. The pulse transfer characteristic maintains constant apparent lamp brilliance independent of variations in accessory power requirements. In an off or in a preheat condition, power transfer to the lamp is reduced to prevent emission of a visible light beam.

Abstract: A fader wheel assembly for a lighting control console includes a fader wheel having a single hub mounted at an acute angle to the top wall of the console. The inclined orientation positions approximately half of smooth, rounded outer wall and rim surfaces above the console top wall in an arrangement that is comfortable for the user. A single bearing locates the wheel as well as a transducer that is supported essentially only by its attachment to the fader wheel. Resilient arms lightly hold the transducer in position.

Abstract: A cover assembly for a wall mounted electrical device enclosure includes a mounting bracket that can be attached to the enclosure and a cover plate that is removeably installed onto the mounting bracket. The mounting bracket includes a rigid latch tang and supports an opposed resilient catch. The face plate includes opposed latch recesses. To install the face plate, the resilient catch is engaged with one latch recess and then is resiliently deformed to permit the latch tang to engage the opposed latch recess. The face plate can be removed only by first moving it in the plane of the wall to deform the resilient catch.

Abstract: An improved plug-in power module for providing a controlled amount of electrical power to one or more remote lighting fixtures or other load is disclosed, the module being configured to sense a ground fault or other current imbalance at the load and, in response, both to trigger the module's circuit breaker to open and to report the occurrence of such a ground fault to a central location. The power module achieves these important functions without adding unduly to the module's complexity or size.